ST-246 (tecovirimat monohydrate) SUSPENSION FORMULATIONS

ABSTRACT

The present invention is directed to a dry suspension for reconstitution containing Tecovirimat (ST-246) powder and simethicone. The dry suspension is dispersed in water to provide an aqueous pharmaceutical suspension formulation for oral administration for treating orthopoxvirus infections and/or eczema vaccinatum. The suspension formulation exhibits excellent stability and good dissolution and has an improved taste and texture.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation application of U.S. application Ser. No. 16/071,119 filed Jul. 19, 2018 which is a § 371 National Phase application based on PCT/US2017/017915 filed Feb. 15, 2017 which claims the benefit of U.S. provisional application No. 62/295,710 filed Feb. 16, 2016 the subject matter of each of which is incorporated by reference in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with U.S. government support under Contract No.: IIIISO100201100001C awarded by the Biomedical Advanced Research and Development Authority (BARDA). The U.S. government has certain rights in this invention.

FIELD OF THE INVENTION

The present invention relates to a novel oral powder for suspension (dry suspension) containing Tecovirimat (ST-246) powder for reconstitution and a process for making the dry suspension. The dry suspensions are dispersed in water to provide aqueous pharmaceutical suspension formulations for oral administration.

BACKGROUND OF THE INVENTION

Throughout this application, various publications are referenced within the text. The disclosure of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art as known to those skilled in therein as of the date of the invention described and claimed herein.

Historically, variola virus, the etiologic agent of smallpox, has been estimated to have killed, crippled, or disfigured nearly 10% of the human population prior to eradication (1). Smallpox is highly communicable and carries exceptionally high morbidity. Secondary attack rates among unvaccinated members of households in which someone had smallpox have been reported to range from r30% to 80%. Mortality rates range from 1% for variola minor to 30% for variola major. With the advent of biowarfare as an instrument of terrorism, smallpox can no longer be thought of as a disease of historic impact only.

There are currently no therapies other than early vaccination that can alter the outcome of disease or potentially prevent disease in a population that has been exposed to smallpox. Vaccination carries an inherent risk of adverse events for certain immunosuppressed recipients and even some healthy recipients (2). Moreover, vaccination is effective only if administered within 4 days post-exposure. Thus, antiviral drugs used alone or potentially in combination with vaccination can be used to treat individuals during the window of vulnerability which occurs prior to development of protective immunity. Additionally, antiviral drugs could also be used in the treatment of zoonotic poxvirus disease in humans, such as monkeypox.

ST-246 (4-trifluoromethyl-N-(3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(III)-yl)-benzamide)(Tecrovirmat), has recently emerged as a potent candidate against orthopoxvirus. Several studies evaluating ST-246 for activity against orthopoxviruses have demonstrated excellent in vitro and in vivo efficacy (3, 4). When evaluated in vitro against vaccinia virus (VV), cowpox virus (CV), ectromelia virus (ECTV), monkeypox, camelpox, and variola viruses, ST-246 inhibited virus replication by 50% (50% effective concentration [EC50]) at or below a concentration of 0.07 μM. With animal models using lethal infections with ECTV, VV, or CV, ST-246 was reported to be nontoxic and highly effective in preventing or reducing mortality even when treatments were delayed up to 72 h post-viral inoculation (3, 4). ST-246 was also evaluated with the nonlethal mouse tail lesion model using intravenous VV. When ST-246 was administered orally twice a day at 15 or 50 mg/kg of body weight for 5 days, the tail lesions were significantly reduced (4). Most recently, an infant was given ST-246 as an FDA-authorized emergency treatment for eczema vaccinatum which developed after exposure to the parent's predeployment military smallpox immunization (5).

Given the high efficacy of ST-246 antiviral therapy against smallpox and a lack of FDA-approved medications for the treatment of smallpox infection, there is clearly a need for developing safe and effective ST-246 formulations that can be administered by various routes of administration. However, the poor solubility of ST-246 in water and in pharmaceutically acceptable pH buffers and commonly used pharmaceutical vehicles such as co-solvents, surfactants, complexing agents, and lipids creates an impediment to making safe and effective ST-246 liquid formulations.

Thus, there is a critical need in the pharmaceutical and other biological based industries to formulate water insoluble ST-246 into liquid suspensions for oral, parenteral, or topical administration.

However, the preparation of an aqueous pharmaceutical suspension formulation from micronized ST-246 presents problems that are difficult to overcome, such as retaining the colloidal stability, preventing particle size growth and foaming.

Furthermore, once an aqueous suspension has been prepared, sedimentation of the suspension should be avoided. However, if sedimentation arises, the restoration of the suspension must be achieved as easily and as quickly as possible and advantageously this should be achieved by simply shaking the mixture by hand.

Failure to attain rapid reconstitution of the suspension results in an unacceptably high risk of a dosage error. Furthermore, rapid reconstitution is crucial given that the suspension is often dispensed using a dropper or a dispensing syringe, thereby requiring a stable liquid suspension which is able to flow freely from the dispensing devices and ensure that significantly less material sticks therein.

Additionally, foaming of the suspension formulation should be avoided, given that this also results in the dosage being imprecise and uncertain.

Finally, suspension formulations that are used for oral administration, particularly for pediatric use, must not have a bitter taste.

SUMMARY OF THE INVENTION

The present invention provides an oral powder for suspension (dry suspension) containing 4-trifluoromethyl-N-(3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2-(1H)-yl)-benzamide, commonly known as Tecovirimat or ST-246, granulated powder and simethicone, which is suitable for reconstitution.

The present invention also provides a process for making the dry suspension comprising mixing ST-246 powder with simethicone.

The present invention further provides an aqueous pharmaceutical suspension formulation comprising ST-246, simethicone and a suspending agent for oral administration.

Additionally, the present invention provides a process for making the aqueous pharmaceutical suspension formulation comprising dispersing the dry suspension and a suspending agent in water.

The present invention also provides methods of treating orthopoxvirus infections and/or eczema vaccinatum comprising administering to a subject in need thereof an aqueous pharmaceutical suspension formulation according to the present invention.

These and other objects, advantages, and features of the invention will become apparent to those persons skilled in the art upon reading the details of the methods and formulations as more fully described below.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the % ST-246 release from formulations DS 54, 55, 57 and 58.

FIG. 2 shows the % ST-246 release from formulations DS 75, 77, 83 and 84.

FIG. 3 shows the dissolution of ST-246 from formulations DS 85, 86, and 87.

FIG. 4 shows the % ST-246 release from formulation DS 88 at different blending times.

FIG. 5 shows the % ST-246 release from DS 88 at different lubrication times.

FIG. 6 shows the % ST-246 release from DS 89 and 90.

FIG. 7 shows the % ST-246 release from DS 91 and 92.

FIG. 8A shows an observation that when passing undiluted simethicone through #20 screen the simethicone granules stick on the screen. FIG. 8B shows an observation when passing undiluted simethicone granules through #20 screen the simethicone granules stick on the screen. FIG. 8C shown an observation that when passing pre-diluted simethicone through #20 screen the simethicone granules passed through the screen easily without sticking. FIG. 8D shows an observation that when passing co-milled simethicone-Tecovirimat granules through #20 screen the co-milled simethicone-Tecovirimat granules passed easily through the screen without sticking.

FIG. 9 shows retained clumps on #20 screen after sieve shaking of 100 g DS-92.

FIG. 10 shows % ST-246 release from DS 93 and 94.

FIG. 11 shows flavor profile definitions, including amplitude, amplitude scale, character notes, intensity scale and aftertaste.

FIG. 12 shows a time intensity profile of musty aromatic off-notes, bitterness and tannin mouthfeel of the Tecovirimat granules lingered at patient-perceptible levels (≥1) for about 3 minutes in the aftertaste.

FIG. 13 shows a time intensity profile of Tecovirimat formulation #4 (micronized API).

FIG. 14 shows a time intensity profile of formulation #1 (strawberry)

FIG. 15 shows a time intensity profile of formulation #2 (cherry)

DETAILED DESCRIPTION OF THE INVENTION

Tecovirimat (ST-246) is an antiviral agent used for smallpox and related orthopoxviruses. A suitable oral formulation, according to the present invention, is particularly useful in pediatric and/or geriatric populations. The typical maximum dosage is 1200 mg/day. The drug has very low water solubility over the physiologically relevant pH range, namely approximately 2 μg/mL over a pH range of 1.2 to 6.5. Its solubility increases slightly above pH 6.5, however the chemical stability declines. The solution stability is optimum in the pH 4 to 7 range, for example the pH 3 to 5 range.

Due to low solubility, preferably the ST-246 is micronized in order to improve dissolution rate. ST-246 has the potential to undergo supersaturation and crystallization with increased particle size in an aqueous based vehicle, and hence, providing an acceptable ready-to-use liquid/suspension dosage form with better stability and longer shelf-life represents a major challenge.

Additionally, when forming a suspension formulation containing ST-246, a wetting agent, such as a surfactant, is typically used to improve wetting of ST-246 particles, and also to improve dissolution and solubility. However, the presence of a surfactant usually leads to foaming and results in the formulation tasting bitter and having an unpleasant odor.

The present invention provides a powder for a reconstitution product (dry suspension) comprising ST-246 granulated powder and simethicone which when suspended in water exhibits acceptable stability and dissolution. Furthermore it has been found that the use of simethicone with ST-246 provides excellent foam control upon reconstitution.

The present invention provides a similar drug release profile, a critical product attribute for product performance in patients, as compared to capsule oral dosage form of ST-246.

Additionally, the incorporation of additional excipients, flavorings and/or sweeteners to the dry suspension and/or the aqueous pharmaceutical suspension formulation improves the taste and texture of the formulation.

The dry suspension and/or the suspension formulation may also include one or more pharmaceutically acceptable ingredients selected from the group consisting of disintegrants, carriers, diluents, additives, fillers, lubricants, and binders.

Disintegrants may include agar-agar, alginic acid, calcium carbonate, microcrystalline cellulose, croscarmellose sodium, crospovidone, polacrilin potassium, sodium starch glycolate, potato or tapioca starch, pre-gelatinized starch, other starches, clays, other algins, other celluloses, gums, and mixtures thereof.

Preferably, the dry suspension further comprises at least one suspending agent.

The suspending agents may include sorbitol syrup; sugar syrup; synthetic polymers such as carbomer and poloxamer; natural gums such as agar, xanthan gum, and tragacanth; cellulose derivatives (e.g., carboxy methyl cellulose, hydroxyl propyl cellulose or methylcellulose); or hydrogenated edible fiats; emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters, ethyl alcohol or fractionated vegetable oils); and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid).

The dry suspensions can also contain buffer salts, flavoring, coloring and sweetening agents as appropriate.

Furthermore, the dry suspensions may also contain wetting agents and/or surface active agents as appropriate.

Preferably, the wetting agent or surface active agent is sodium dodecyl sulfate, sodium docusate, tweens, spans, brij, or cetrimide.

Preferably, the suspending agent is methylcellulose and/or hydroxypropyl cellulose, and, advantageously, the dry suspension contains both methylcellulose and hydroxypropyl cellulose.

Preferably, the dry suspension contains methylcellulose 400 cps and/or methycellulose 15 cps and, advantageously, the dry suspension contains both methylcellulose 400 cps and methycellulose 15 cps methylcellulose.

Typically, the dry suspension comprises a lubricant, such as calcium stearate, magnesium stearate, mineral oil, light mineral oil, glycerin, sorbitol, mannitol, polyethylene glycol, other glycols, stearic acid, sodium lauryl sulfate, talc, hydrogenated vegetable oil (e.g., peanut oil, cottonseed oil, sunflower oil, sesame oil, olive oil, corn oil, and soybean oil), zinc stearate, ethyl oleate, ethyl laureate, agar, and mixtures thereof.

Advantageously, the lubricant is magnesium stearate.

Excipients include, but are not limited to, agents used to improve taste, suspendability, texture, and flavor. In one embodiment, when the dry suspension contains an excipient, the excipient is advantageously lactose monohydrate. When present, the total amount of excipients are typically present in an amount of about 10 wt % to about 20 wt %.

The dry suspension may also contain a further antifoaming agent.

Preferably, the dry suspension also contains a sweetener, such as sucralose.

Advantageously, the dry suspension contains a flavoring such as strawberry or black cherry.

The ST-246 may be selected from the group consisting of ST-246 polymorph Form I, ST-246 polymorph Form II, ST-246 polymorph Form III, ST-246 polymorph Form IV, ST-246 polymorph Form V and ST-246 polymorph Form Vi.

The ST-246 may be micronized and/or granulated with excipients, but is advantageously micronized and granulated powder.

Furthermore the simethicone may be in granular form or may be in liquid form and adsorbed on lactose monohydrate. Advantageously, the simethicone is in granular form.

The dry suspension typically contains between 10 to 70 wt % of ST-246, and preferably between 15 to 40 wt % of ST-246.

The dry suspension usually contains between 0.2 to 6.0 wt % simethicone, and preferably between 0.4 to 5.0 wt % simethicone.

Preferably, the dry suspension contains between 1 to 5 wt % of methylcellulose, and advantageously, between 2 to 3 wt % of methylcellulose.

Preferably, the dry suspension contains between 1.0 to 30 wt % of hydroxypropylcellulose, and, advantageously, between 2 to 20 w % of hydroxypropylcellulose.

When the dry suspension contains a lubricant, typically the lubricant is present in the amount 0.1 to 1.0 wt %.

Similarly, when the dry suspension contains a sweetener, typically the sweetener is present in the amount of between 1.0 to 3.0 wt %, and when the dry suspension contains a flavoring, typically the flavoring is also present in the amount of between 0.1 to 1.0 wt %.

The dry suspension preferably has an active pharmaceutical ingredient (API) particle size of ST-246 of between 0.5 to 20 μm, or between 0.5 to 10 μm, or between 1 μm and 5 μm, and, advantageously, between 1 to 10 μm.

It has been found that the higher the API particle size, the slower the dissolution rate.

The present invention also provides an aqueous pharmaceutical suspension formulation comprising the dry suspension dispersed in water.

Typically the suspension, either dry or liquid, contains a suspending agent which is preferably selected from the group consisting of hydromellose, hydroxyethylcellulose, carrageenans, methylcellulose, xanthan gum, povidone, hydroxypropyl cellulose, microcrystalline cellulose, carboxymethylcellulose and sodium alginate.

When the suspension contains water and a suspending agent this is typically referred to as a ‘formulation vehicle’.

Typically, the formulation, upon reconstitution with water, has a pII between 3 and 8, preferably between 5 and 7.

The present invention also provides a method of treating orthopoxvirus infections and/or eczema vaccinatum comprising oral administration to a subject in need thereof the above mentioned formulation. Typically, the formulation of the present invention is administered in an amount such that the dose of ST-246 is 200 mg to 2000 mg per day, preferably 400 mg to 2000 mg per day, and most preferably 600 mg to 1200 mg daily. Dosage is typically adjusted according to body weight, particularly in pediatric populations.

Additionally, the present invention also provides a process of making the dry suspension which involves mixing ST-246 or ST-246 granulated powder with simethicone.

Optionally, at least one suspending agent, at least one lubricant, at least one excipient, at least one further anti-foaming agent, at least one sweetener and/or at least one flavoring may be mixed with the ST-246 and the simethicone.

Advantageously, mixing is carried out using geometric mixing.

Finally, the present invention provides a method of making the above mentioned formulation wherein the dry suspension is dispersed in water, and wherein the water advantageously contains a suspending agent as herein described above.

As used herein. “percent,” “percentage” or the symbol “%” means the percent of the component indicated in the composition based on the amount of the carrier present in the composition, on a weight/weight (w/w), weight/volume (w/v) or volume/volume (v/v) concentration, as indicated with respect to any particular component, all based on the amount of the carrier present in the composition. Thus, different types of carriers can be present in an amount of up to 100% as indicated, which does not preclude the presence of the API, the amount of which can be indicated as a % or as a certain number of mg present in the composition or a certain number of mg/mL present, where the % or mg/mL is based on the amount of the total carrier present in the composition. Certain types of carriers can be present in combination to make up 100% of the carrier.

As used herein, the terms “Tecovirimat” and “ST-246” refer to the compound 4-trifluoromethyl-N-(3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2-(1H)-yl)-benzamide.

The invention is further described by the examples given below.

EXAMPLES Example 1. Production of a Dry Suspension Containing Tecrovirmat Monohydrate (ST-246) for Reconstitution, 200 mg

A stable oral powder containing ST-246 was prepared, particularly for pediatric and % or geriatric application. The development of the powder involved the following stages;

-   -   1. Formulation and evaluation of various dry suspensions.     -   2. Optimization and evaluation of various level of anti-foaming         agents and lubricant and their effect on product properties.     -   3. Optimization and evaluation of blending time and lubrication         time in the product manufacturing process and its effect on         product properties.     -   4. Manufacture of batches for stability studies.         Materials: The Following Materials were Used.

S. # .Material Supplier/Lot# 1 Tecovirimat Monohydrate, micronized, Siga Technologies for discriminatory dissolution method Lot # SG-10C12-T1039 development (Trial #2, d90 = 21.51 μm) 2 Tecovirimat Monohydrate, micronized, Siga Technologies for discriminatory dissolution method Lot # SG-10C12-T1039 development (Trial #3, d90 = 38.74 μm) 3 Tecovirimat Monohydrate, micronized, Siga Technologies for discriminatory dissolution method Lot# SG-10C12-T1039 development (Trial #4, d90 = 81.53 μm) 4 Tecovirimat Granulate Siga Technologies Lot # 1302679 5 Tecovirimat Granulate Siga Technologies Lot # 1401165 6 Colloidal silicon dioxide, NF Cabot (Cabosil MSP) Lot #1222272 7 Croscarmellose sodium, NF FMC Biopolymer (AcDiSol) Lot # TN12824921 8 Lactose monohydrate, NF DFE (SuperTab11SD) Lot # 10705838 9 Lactose monohydrate, NF DFE (SuperTab11SD) Lot # 10700181 10 Lactose monohydrate, NF DFE (SuperTab11SD) Lot # 10737298 11 Microcrystalline cellulose, NF FMC Biopolymer (Avicel PII101) Lot # P113825526 12 Ilypromellose, USP Dow (Methocel E3 LV Premium) Lot # 1D020124L1 13 Sodium lauryl sulfate, NF Spectrum Lot # 1DB0596 14 Purified Water, USP Ricca Chemicals Lot # 4409016 15 Sucralose, NF Spectrum Lot # 1CF0697 16 Sucralose, NF Spectrum Lot # 1DF0586 17 Strawberry flavor, #133.16296 Bell Flavors 18 Black cherry nat type flavor Kerry Lot # 260314 19 Simethicone, USP Nusil Technologies (MED-340, simethicone content 100%) Lot # 63865 20 Simethicone Granular Solid, USP Nusil Technologies (MED-342, simethicone content 30'%) Lot # 63775 21 Simethicone Granular Solid, USP Nusil Technologies (MED-342, simethicone content 30%) Lot # 66777 27 Simethicone Granular Solid, USP Nusil Technologies (MED-342, simethicone content 30%) Lot # 67719 23 Magnesium stearate, NF Mallinckrodt (HyQual) Lot # 1301000109 24 Crospovidone, USP/NF BASF (Kollidon CL-M) Lot # 10204988Q0 25 Povidone, USP/NF BASF (Kollidon 12PF) Lot # 12714424U0 26 Povidone, USP/NF BASF (Koi Udon, 90F) Lot # 45877768E0 27 Hypromellose Dow (Methocel F50) Lot # 2L03012N21 28 Hypromellose Dow (Methocel E50) Lot # 2C01012N23 29 Methylcellulose, USP Dow (Methocel A4M Premium) Lot # 2E19012N11 30 Methylcellulose, 400 cps, USP Spectrum Lot # 2CJ0081 31 Methylcellulose, 400 cps, USP Spectrum Lot # 2DC0205 32 Methylcellulose, 15 cps, USP Spectrum Lot # 2DE0263 33 Hydroxypropyl cellulose, NF Ashland (Klucel JF Pharm) Lot # 38296 34 Hydroxypropyl cellulose, NF Ashland (Klucel JXF Pharm) Lot # 40289 35 Hydroxypropyl cellulose, NF Ashland (Klucel HF Pharm) Lot # 49264 36 Hydroxypropyl cellulose, NF Ashland (Khtcel MF Pharnt) Lot # 38949 37 Hydroxylethyl cellulose, NF Ashland (Natrosol 250L Pharm) Lot # J1967 38 Carrageenan, NF FMC Biopolymer (Gelcarin GP3 79) Lot # 50218031 39 Carrageenan, NF FMC Biopolymer (SeaSpen PF) Lot # 20226021 40 Microcrysial line Cellulose and Sodium FMC Biopolymer Carboxymethylcellulose, NF Lot # B1204C (Avicel RC-581) 41 Microcrystalline Cellulose and Sodium FMC Biopolymer Carboxymethyl cellulose, NF Lot # EN13825521 (Avicel CL-611) 42 Microcrystalline Cellulose and Sodium FMC Biopolymer Carboxymethy l cellulose, NF Lot # DN13825459 (Avicel RC-591) 43 Sodium Alginate, USP/NF FMC Biopolymer (Protanal LFR5/60) Lot # H191208 44 Xanthan gum, USP/NF CP Kelco (Xantural 75) Lot # 2B4685K 45 Simethicone 50% Powder AIC Lot # 4060-50205

Two typical dry suspensions are shown in Table. The dry suspensions according to the present invention contain granules of ST-246 and additional excipients to improve taste suspendability, texture and favor.

TABLE 1 Compo- Compo- sition of sition of Formulation Formulation No. Ingredient DS83 (mg) DS84 (mg) 1 Tecovirimat granulate 346.5 346.5 2 Lactose monohydrate (SuperTab 11SD, 93.0 0.0 DMV Fonterra Excipients) 3 Klucel JF Pharm (Ashland) 125.0 118.0 4 Sucralose, USP 10.0 10.0 5 Flavor, black cherry (Virginia Dare, 3.0 3.0 #23950) 6 Simethicone granular solid (NuSil 20.0 20.0 MED-342) 7 Magnesium stearate 2.5 2.5 Total 600.0 500.0

Example 2: Development of the Dry Suspensions for Reconstitution, 200 mg

The composition of the Tecovirimat granulate is shown in Table 2. An oral powder for suspension using a suspending agent containing microcrystalline cellulose and sodium carboxymethylcellulose (Avicel CL-611) was used as a Target formulation is shown in Table 3. The target formulation exhibits good physical properties. However, the xanthan gum which is co-processed along with microcrystalline cellulose results in coagulation behavior during the dissolution tests due to the interaction with the surfactant used in the dissolution medium and thus poor drug release.

TABLE 2 Composition of ST-246 commercial granules Quantity per Unit S. No Ingredients (mg) 7 ST-246, Monohydrate, micronized 209.00 Microcrystalline Cellulose, NF (Avicel PH101) 49.628 3 Lactose Monohydrate, NF (Supertab 11SD) 33.15 4 Croscarmellose Sodium. NF (Ac-di-sol SD-711) 31.2 5 Colloidal Silicone Dioxide, NF (Cab-O-Sil ® 1.95 M5P) 6 Hypromellose, USP (Methocel E3) 13.65 7 Sodium Lauryl Sulfate, NF 7.80 8 Purified Water*, USP q.s. Total 346.4 *water is removed during drying

TABLE 3 ST-246 oral powder for suspension (Target Formulation) Prototype 1 Prototype 2 (mg per (mg per Ingredient dose) dose) ST-246, granulate 346.5 346.5 Lactose monohydrate (SuperTab 11SD, DMV 503.3 505.1 Fonterra Excipients) Simethicone granular solid, (NuSil MED-342) 10.0 10.0 Aviccl CL-611, NF (FMC BioPolymer) 125.0 125.0 Sucralose, USP 10.0 10.0 Flavor, strawberry (Kerry Item: U1-721636) 5.0 — Flavor, black cherry (Kerry Item: U1-717664) — 3.0 FD&C Red #3 0.10 — FD&C red #40 55 0.3 Methylparaben, NF 0.08 0.08 Propylparaben, NF 0.02 0.02 Total 1,000.0 1,000.0

Example 3: Screening and Selection of Suspending Agent

ST-246 granules prepared for capsule dosage form were used for the preparation of ST-246 oral powder for reconstitution, 200 mg. To evaluate the suspendability of the granules in various suspending agents, various suspending agents were dispersed in 50 mL purified water (Table 4). Concentrations of suspending agents in formulations DS-1 to DS-16 were produced according to the maximum potential from FDA Inactive Ingredient Guide (IIG). A placebo was prepared and compared visually with the target formulation and the concentration of suspending agent was adjusted accordingly in formulation DS-17 to DS-38

TABLE 4 Composition and Observation of Suspending Agent Placebo Solutions/Suspensions. Consistency (Visual observation in Polymer comparison Viscosity quantity with target (cps, target equilvalent to formulation formulation Brand Formulation 10 doses Disperse Overnight viscosity viscosity Chemicals name ID (concentration) Appearance speed sedimentation +++++) 50-100 cps) Crospovidone Kollidon DS-1 2.500 g white fast sedimentation, less viscous not CL-M (5%, w/v) suspension easy to ++ measured redisperse by shaking Povidone (PVP) Kollidon DS-2 0.750 g colorless fast none less viscous not 90 F (1.5 %, w/v) solution + measured DS-17 1.500 g colorless fast none less viscous not (3%, w/v) solution + measured DS-29 3.000 g colorless fast none comparable 55.8 (6%, w/v) solution ++++ Kollidon DS-3 0.750 g colorless fast none less viscous not 12 PF (1.5%, w/v) solution + measured DS-18 1.500 g colorless fast none less viscous not (3%, w/v) solution + measured DS-30 3.000 g colorless fast none less viscous not (6%, w/v) solution ++ measured Hypromellose Methocel DS-4 1.500 g colorless slow none comparable 43.1 (HPMC) F50 (3%, w/v) solution +++++ Methocel DS-5 1.500 g colorless slow none comparable 85.6 E50 (3%, w/v) solution +++++ DS-19 0.750 g colorless slow none less viscous not (1.5%, w/v) solution ++ measured Methylcellulose Methocel DS-6 0.595 g colorless slow none more not (MC) A4MP (1.19%, w/v) solution viscous measured ++++++ DS-26 0.250 g colorless slow none comparable 24.9 (0.5%, w/v) solution ++++ Methyl DS-7 0.595 g colorless slow none comparable not cellulose, (1.19%, w/v) solution +++++ measured 400 cps DS-27 0.250 g colorless slow none comparable 17.1 (0.5%, w/v) solution ++++ Hydroxypropyl Klucel DS-8 3.350 g colorless slow none more not cellulose (HPC) JF Pharm (6.7%, w/v) solution viscous measured +++++++ DS-20 0.750 g colorless slow none less viscous not (1.5%, w/v) solution ++ measured DS-31 1.500 g colorless slow none comparable 20.4 (3%, w/v) solution ++++ Klucel DS-9 3.350 g colorless slow none more not HF (6.7%, w/v) gel viscous, gel, measured Pharm high viscosity DS-21 0.500 g colorless slow none more not (1.0%, w/v) solution viscous measured ++++++++ DS-33 0.375 g colorless slow none comparable 123.9  (0.75%, w/v) solution ++++++ Klucel DS-10 3.350 g colorless slow none more not MF (6.7%, w/v) gel viscous, gel, measured Pharm high viscosity DS-22 0.500 g colorless slow none more not (1.0%, w/v) solution viscous measured +++++++ DS-34 0.375 g colorless slow none comparable 71.0 (0.75%, w/v) soluton +++++ Hydroxyethyl Natrosol DS-11 1.500 g yellowish fast none comparable 14.9 cellulose (HEC) 250L (3%, w/v) solution ++++ Pharm DS-28 2.000 g yellowish fast none comparable not (4%, w/v) solution ++++ measured Carrageenan Gelcarin DS-12 0.750 g yellowish slow none more not GP379 (1.5%, w/v) gel viscous, gel, measured high viscosity DS-23 0.200 g yellowish slow none comparable 65.5 (0.4%, w/v) solution +++++ SeaSpen DS-13 0.750 g milky slow none more not PF (1.5%, w/v) gel viscous, gel, measured high viscosity DS-24 0.200 g milky slow none comparable 20.1 (0.4%, w/v) solution ++++++ Microcrystalline Avicel DS-14 1.500 g white fast none more not cellulose/sodium RC-581 (3%, w/v) suspension viscous measured carboxymethyl +++++++ cellulose DS-35 1.250 g white fast none comparable 84.3 (MCC/CMCNa) (2.5%, w/v) suspension ++++++ Avicel DS-15 1.500 g white fast none more not CL-611 (3%, w/v) suspension viscous measured +++++++ DS-36 1.250 g white fast none comparable 35.4 (2.5%, w/v) suspension +++++ Avicel DS-37 1.250 g white fast none comparable 93.8 RC-591 (2.5%, w/v) suspension ++++++ Sodium Protanal DS-16 0.062 g colorless fast none less viscous not Alginate LFR (0.123%, w/v) solution + measured 5/60 DS-25 0.800 g yellowish slow none less viscous not (1.6%, w/v) solution ++ measured DS-32 1.600 g yellowish slow none less viscous not (3.2%, w/v) solution ++++ measured DS-38 2.000 g yellowish slow none comparable 32.4 (4%, w/v) solution +++++

Povidone (Kollidon 90 F) 6%, Hypromellose (Methocel F 50 and E50) 3%, Methylcellulose (Methocel A4MP), Methyl Cellulose 400 cps 0.5%, Hydroxypropyl cellulose (Klucel HF and MF) 0.75%, Hydroxy Ethyl Cellulose (Natrosol 250 L Pharm) 3%, Avicel RC-581—2.5%. Avicel RC-591—2.5% and Sodium alginate 4% show comparable viscosity to the Target formulation containing Avicel CL-611.

The suspending agent concentrations with comparable consistency to that of the Target formulation (containing Avicel CL-611 as suspending agent) were selected as the formulation viscosity modifier.

Example 4: Formulation of Suspensions by Mixing ST-246 Granules with Formulation Vehicles

To evaluate the suspendability of ST-246, ingredients such as sucralose, simethicone (adsorbed on lactose monohydrate) and suspension polymers were added. Lactose monohydrate was added to make up the weight of the composition. These ingredients were mixed with the selected suspending agent vehicle concentration from Example 3. The resultant compositions are given in Table 5.

The formulation procedure included:

-   -   1. Adsorbing I g of simethicone (MED-340, liquid) on 19 g         lactose monohydrate (SuperTab 11SD).     -   2. Geometric mixing of the ST-246 granules, sucralose,         simethicone adsorbed on lactose, and lactose monohydrate to make         5 g (5 doses) blends considering the quantity of polymer         quantity sufficient (Q.S.) to 25 mL of vehicle.     -   3. Dispersing the blend in Q.S. to 25 mL of formulation vehicle         prepared in Example 3.     -   4. Evaluation of the sedimentation, redispersibility, and pH of         the suspensions.     -   5. Transfer of each of about 5 mL of suspension in screw cap         glass vials, to store the samples at room temperature, at 2 to         8° C. and at 40° C./75% RH for 14 Days and recording the         observations. Table 6 shows the results of physical properties         of suspensions.

TABLE 5 Composition of suspensions-Suspending Agent Selection Quantity (g) Equivalent to 5 doses S.# Ingredients DS-39 DS-40 DS-41 DS-42 DS-43 DS-44 DS-45 DS-46 1 ST-246 Granules 1.733 1.733 1.733 1.733 1.733 1.733 1.733 1.733 2 Sucralose, NF 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 3 Simethicone, USP (MED-340) 0.025 0.025 0.025 0.025 0.025 0.025 0.025 0.025 Lactose Monohydrate, NF, 0.475 0.475 0.475 0.475 0.475 0.475 0.475 0.475 (SuperTab 11SD) 5 Lactose Monohydrate, NF 1.967 1967 1.967 2.617 2.617 2.592 2.592 1.217 (SuperTab 11SD) 6 Hypromellose (Methocel F 50), 25.750 — — — — — — — 3% Dispersion Hypromellose (Methocel E 50), — 25.750 — — — — — — 3% Dispersion Hydroxyethyl cellulose — — 25.750 — — — — — (Natrosol 250L), 3% Dispersion Carrageenan (Iota) (Gelcarin GP379), — — — 25.100 — — — — 0.4% Dispersion Carrageenan (Iota) (SeaSpen PF), — — — — 25.100 — — — 0.4% Dispersion Methyl Cellulose (Methocel A4MP), — — — — — 25.125 — — 0.5% Dispersion Methyl Cellulose, 400 cps, 0.5% Dispersion — — — — — — 25.125 — Povidone (Kollidon 90F), 6% Dispersion — — — — — — — 26.500 Hydroxypropyl cellulose (Klucel JF Pharm), — — — — — — — — 3% Dispersion Hydroxypropyl cellulose (Klucel HF Pharm), — — — — — — — — 0.75% Dispersion Hydroxypropyl cellulose (Klucel MF Pharm), — — — — — — — — 0.75% Dispersion Microcrystalline cellulose and carboxymethyl — — — — — — — — cellulose (Avicel RC-581), 2.5% Dispersion Microcrystalline cellulose and carboxymethyl — — — — — — — — cellulose (Avicel CL-611), 2.5% Dispersion Microcrystalline cellulose and carboxymethyl — — — — — — — — cellulose (Avicel RC-591), 2.5% Dispersion Sodium Alginate (Protanal LFR 5/60), — — — — — — — — 4% Dispersion S.# Ingredients DS-47 DS-48 DS-49 DS-50 DS-51 DS-52 DS-53 1 ST-246 Granules 1.733 1.733 1.733 1.733 1.733 1.733 1.733 2 Sucralose, NF 0.050 0.050 0.050 0.050 0.050 0.050 0.050 3 Simethicone, USP (MED-340) 0.025 0.025 0.025 0.625 0.025 0.025 0.025 Lactose Monohydrate, NF, 0.475 0.475 0.475 0.475 0.475 0.475 0.473 (SuperTab 11SD) 5 Lactose Monohydrate, NF 1.967 2.530 2.530 2.092 2.092 2.092 1.717 (SuperTab 11SD) 6 Hypromellose (Methocel F 50), — — — — — — — 3% Dispersion Hypromellose (Methocel E 50), — — — — — — — 3% Dispersion Hydroxyethyl cellulose — — — — — — — (Natrosol 250L), 3% Dispersion Carrageenan (Iota) (Gelcarin GP379), — — — — — — — 0.4% Dispersion Carrageenan (Iota) (SeaSpen PF), — — — — — — — 0.4% Dispersion Methyl Cellulose (Methocel A4MP), — — — — — — — 0.5% Dispersion Methyl Cellulose, 400 cps, 0.5% Dispersion — — — — — — — Povidone (Kollidon 90F), 6% Dispersion — — — — — — Hydroxypropyl cellulose (Klucel JF Pharm), 25.750 — — — — — — 3% Dispersion Hydroxypropyl cellulose (Klucel HF Pharm), — 25.187 — — — — — 0.75% Dispersion Hydroxypropyl cellulose (Klucel MF Pharm), — — 25.187 — — — — 0.75% Dispersion Microcrystalline cellulose and carboxymethyl — — — 25.625 — — — cellulose (Avicel RC-581), 2.5% Dispersion Microcrystalline cellulose and carboxymethyl — — — — 25.625 — — cellulose (Avicel CL-611), 2.5% Dispersion Microcrystalline cellulose and carboxymethyl — — — — — 25.625 — cellulose (Avicel RC-591), 2.5% Dispersion Sodium Alginate (Protanal LFR 5/60), — — — — — — 26.000 4% Dispersion

The sedimentation coefficients were determined by measuring the height of the suspension in a 40 cc vial divided by the height of the sediment in a vial. Sedimentation coefficient versus time is used as an indicator as to the stability of suspension over the time.

The redispersibility was evaluated by centrifuging the suspension in Eppendorf tube at 5000 rpm for 10 minutes followed by shaking manually or with wrist action shaker, if the sediment in centrifuge suspended again, it was recorded as “redispersible.”

TABLE 6 Characterization of Physical Stability of Selected Formulations DS-39 DS-40 DS-41 DS-42 D5-43 DS-44 DS-45 DS-46 Methocel Methocel Natrosol Gelcarin SeaSpen Methocel MC, Kollidon F50 E50 250L GP379 PF A4MP 400 cps 90F Formulation ID 3% 3% 3% 0.4% 0.4% 0.5% 0.5% 6% Polymer w/v w/v w/v w/v w/v w/v w/v w/v Observations 1 Appearance White White White White White White White White dispersion dispersion dispersion dispersion dispersion dispersion dispersion dispersion 2 Sedimentation 100 100 1.00 1.00 1.00 1.00 1.00 1.00 Coeff (10 min) 3 Sedimentation 1.00 1.00 1.00 1 00 1.00 1.00 1.00 1.00 Coeff (30 min) 4 Sedimentation 1.00 1.00 0.72 0.46 1.00 1.00 1.00 0.51 Coeff (12 h) 5 Sedimentation 100 1.00 0.58 0.38 1.00 1.00 0.92 0.41 Coeff (24 h) 6 Observation None None None None None Noite None None at the time of mixing the solids with the formulation vehicle 7 Redispersibility No No Redispersible Redispersible No No Redispersible Redispersible after 24 hours sedimentation sedimentation sedimentation sedimentation (gentle shaking) 8 pH 5.62 5.81 5.57 5.30 6.67 5.71 5.78 5.67 Stability: 2-8° C. for 14 days 1 Appearance white white white white white white white white (Color) 2 Signs of two two almost clear uni- two two clear Creaming, layers layers clear supernatant form layers layers supernatant flocculation supernatant 3 Sedimentation 0.98 0.99 0.34 0.34 0.97 0.97 0.95 0.31 Coeff 4 Redispersibility redispersible redispersible redispersible redispersible redispersible redispersible redispersible redispersible Stability: 40° C./75% RH for 14 days 1 Appearance white white white white white white white white (Color) 2 Signs of two two clear clear clear clear clear clear Creaming, layers layers supernatant supernatant supernatant supernatant supernatant supernatant flocculation sedimentation sedimentation two two layers layers 3 Sedimentation 0.97 0.98 0.34 0 37 0.34 0.52 0.56 0.34 Coeff 4 Redispersibility redispersible redispersible redispersible redispersible redispersible redispersible redispersible redispersible Stability: Room temperature for 14 days 1 Appearance white white white white white white while white (Color) 2 Signs of two two clear clear clear two two opaque Creaming, layers layers supernatant supernatant supernatant layers layers supernatant flocculation Sedimentation 0.98 0.97 0.30 0.32 0.76 0.65 0.94 0.30 Coeff 4 Redispersibility redispersible redispersible redispersible redispersible redispersible redispersible redispersible redispersible 5 pH 5.62 5.58 5.49 5.25 6.77 5.65 5.66 5.44 DS-47 DS-48 DS.49 DS-50 DS-51 DS-52 DS-53 Klucel Klucel Klucel Avicel Avicel Avicel Protanal Formulation ID JF HF MF RC-581 CL-611 RC-591 LFR5/60 Polymer 3% w/v 0.75% w/v 0.75% w/v 2.5% w/v 2.5% w/v 2.5% w/v 4% w/v Observations 1 Appearance White White White White White White White dispersion dispersion dispersion dispersion dispersion dispersion dispersion 2 Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Coeff (10 min) 3 Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Coeff (30 min) 4 Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 0.27 Coeff (12 h) 5 Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 0.23 Coeff (24 h) 6 Observation Thickening Thickening Thickening None None None Thinning of at the time of of of formulation of mixing formulation formulation, formulation, after the solids gel gel overnight with the standing formulation vehicle 7 Redispersibility No No No No No No Redispersible after 24 hours sedimentation sedimentation sedimentation sedimentation sedimentation sedimentation but (gentle shaking) agglomerates 8 pH 5.76 Not Not 5.58 5.56 5.57 5.16 checked checked Stability: 2-8° C. for 14 days 1 Appearance white Not Not while white white white (Color) checked checked 2 Signs of two layers creamy, uniform creamy clear Creaming, phase supernatant flocculation separation 3 Sedimentation 0.98 0.83 1.00 1.00 0.21 Coeff 4 Redispersibility redispersible redispersible redispersible redispersible redispersible Stability: 40° C./75% RH for 14 days 1 Appearance white Not Not white white white white (Color) checked checked 2 Signs of a thin creamy, uniform creamy clear Creaming, clear phase supernatant flocculation supernatant, separation a thick flocculation layer 3 Sedimentation 0.59 0.78 1.00 1.00 0.34 Coeff 4 Redispersibility redispersible redispersible redispersible redispersible redispersible redispersible redispersible Stability: Room temperature for 14 days 1 Appearance white white white white white white white (Color) 2 Signs of opaque very very creamy, uniform uniform clear Creaming, supernatant viscous gel viscous gel phase supernatant flocculation separation 3 Sedimentation 0.42 1.00 1.00 0.84 1.00 1.00 0.33 Coeff 4 Redispersibility redispersible redispersible redispersible redispersible redispersible redispersible redispersible 5 pH 5.49 4.74 5.65 5.53 5.49 5.50 5.14

Suspensions were prepared using 3% Methocel F50, 3% Methocel E50, 0.5% Methocel A4MP, 0.5% Methylcellulose 400 cps, or 3% Klucel JF as suspending agents and showed comparable physical properties as the Target formulation using 2.5% Avicel CL-611 as a vehicle, and also showed comparable results of physical stability when stored at 2 to 8° C., room temperature and at 40° C./75% RH for the reconstitution study.

Example 5: Formulation and Evaluation of Powders for Reconstitution Using Selected Polymers

Solid blends (including suspending agents selected in Example 4) were formulated, and the rates of reconstitution (hydration time) in water were evaluated. Compositions are given in Table 7.

TABLE 7 Composition of solid blends (including suspending agents) for reconstitution (40 mg/ml). Quantity per unit (mg) S.# Ingredients DS-54 DS-55 DS-56 DS-57 DS-58 1 ST-246 Granules* 346.50 346.50 346.50 346.50 346.50 2 Sucralose, NF 10.00 10.00 10.00 10.00 10.00 3 Simethicone, USP 5.00 5.00 5.00 5.00 5.00 (MED-340) 4 Lactose 95.00 95.00 95.00 95.00 95.00 Monohydrate, NF (SuperTab 11SD) 5 Lactose 393.50 393.50 518.50 518.50 393.50 Monohydrate, NF (SuperTab 11SD) 6 Hypromellose 150.00 — — — — (Methocel F50) Hypromellose — 150.00 — — — (Methocel E50) Methyl Cellulose — — 25.00 — — (Methocel A4MP), USP Methyl Cellulose, — — — 25.00 — 400 cps, USP Hydroxypropyl — — — — 150.00 cellulose (Klucel JF Pharm), NF 7 Purified water, — — — — — USP, Q.S. to 5 mL Total 1000.00 1000.00 1000.00 1000.00 1000.00 *granules equivalent to 200 mg Tecovirimat

The formulation procedure was as follows;

-   -   1. Adsorbing of 1 g of simethicone (MED-340, liquid) on 19 g         lactose monohydrate (SuperTab 11SD)     -   2. Geometric mixing of Tecovirimat granules, sucralose, and         simethicone adsorbed lactose, then weighing of quantity         equivalent to 10 units of blend and then geometric mixing with         other components for each formulation;     -   3. Dispersing of the blend in purified water to make Q.S. to 50         mL;     -   4. Observing the rate of reconstitution, sedimentation,         redispersibility, and pH of the suspensions (see Table 8);     -   5. Storing the samples at room temperature, at 2 to 8° C. and at         40° C./75% RH for 14 Days and recording the observations (see         Table 9);     -   6. Conducting a freeze-thawing cycle of 3-day—10° C. and 3-day         room temperature and repeating 5 times and recording the         observations (see Table 10 and 11).

TABLE 8 Observation of reconstitution and 1-day sedimentation of DS-54 to DS-58 DS-54 DS-55 DS-56 DS-57 DS-58 Formulation ID Methocel F50 Methocel E50 Methocel A4MP MC, 400 cps Klucel JF Polymer 3% w/v 3% w/v 0.5% w/v 0.5% w/v 3% w/v Observations T = 0, room temperature 1 Time for 7 7 1 1 2 reconstitution (min) 2 Observation for Still chunks Still chunks No chunks No chunks Small chunks reconstitution remaining at remaining at remaining, remaining, remaining at bottom after bottom after easy to easy to bottom after shaking shaking disperse disperse shaking 3 Appearance (visual) white, uniform white, uniform white, uniform white, uniform white, uniform 4 pH 5.76 5.81 5.86 5.89 5.78 5 Particle size (μm) 3.20 ± 2.56 3.03 ± 1.91 3.85 ± 3.11 3.3 1 ± 2.43 3.86 ± 3.31 6 Forced settling and redispersible redispersible redispersible redispersible redispersible Redispersibility Observations T = 30 min, room temperature 1 Sedimentation Coefficient 1.00 1.00 1.00 1.00 1.00 2 Appearance (visual) white, uniform white, uniform white, uniform white, uniform white, uniform 3 Redispersibility redispersible redispersible redispersible redispersible redispersible Observations T = 1 hr, room temperature 1 Sedimentation Coefficient 1.00 1.00 1.00 1.00 1.00 2 Appearance (visual) white, uniform white, uniform white, uniform white, uniform white, uniform 3 Redispersibility redispersible redispersible redispersible redispersible redispersible Observations T = 24 hr, room temperature 1 Sedimentation Coefficient 1.00 1.00 1.00 0.98 0.95 2 Appearance (visual) white, uniform white, uniform two layers two layers opaque supernatant with floccules 3 Redispersibility redispersible redispersible redispersible redispersible redispersible

TABLE 9 14-Days stability of DS-54 to DS-58 DS-54 DS-55 DS-56 DS-57 DS-58 Formulation ID Methocel F50 Methocel E50 Methocel A4MP MC, 400 cps Klucel JR Polymer 3% w/v 3% w/v 0.5% w/v 0.5% w/v 3% w/v Observations T = 7 days, room temperature 1 Sedimentation 0.95 0.97 0.95 0.96 0.65 Coefficient 2 Appearance two layers two layers two layers two layers opaque (visual) supernatant with floccules 3 Redispersibility redispersible redispersible redispersible redispersible redispersible 4 pH 5.72 5.79 5.77 5.78 5.70 5 Particle 3.33 ± 2.67 3.37 ± 2.29 3.11 ± 1.88 3.37 ± 1.96 3.20 ± 2.13 size (μm) Observations T = 7 days, 2-8° C. 1 Sedimentation 0.97 0.97 0.98 0.99 0.87 Coefficient 2 Appearance two layers two layers two layers two layers opaque (visual) supernatant with floccules 3 Redispersibility redispersible redispersible redispersible redispersible redispersible 4 pH 5.75 5.82 5.81 5.79 5.75 5 Particle 3.13 ± 2.18 3.20 ± 2.30 3.51 ± 2.37 3.37 ± 2.08 3.57 ± 2.52 size (μm) Observations T = 7 days, 40° C./75% RH l Sedimentation 0.35 0.43 0.44 0.41 0.81 Coefficient 2 Appearance milky opaque clear opaque opaque (visual) supernatant supernatant supernatant supernatant supernatant with with floccules floccules 3 Redispersibility redispersible redispersible redispersible redispersible redispersible 4 pH 5.48 5.55 5.53 5.57 5.44 5 Particle 3.51 ± 2.49 3.45 ± 2.54 3.86 ± 2.55 3.96 ± 3.10 3.81 ± 2.37 size (μm) Observations T = 14 days, room temperature 1 Sedimentation 0.96 0.96 0.49 0.96 0.69 Coefficient 2 Appearance two layers two layers two layers, two layers opaque (visual) clear supernatant supernatant with with floccules floccules 3 Redispersibility redispersible redispersible redispersible; redispersible redispersible sedimentation occurs at 30 min after shaking 4 pH 5.68 5.69 5.72 5.71 5.64 5 Particle 3.69 ± 2.45 3.54 ± 2.68 13.51 ± 2.78 3.68 ± 2.95 3.48 ± 2.66 size (μm) Observations T = 14 days, 2-8° C. 1 Sedimentation 0.96 0.96 0.96 0.95 0.90 Coefficient 2 Appearance two layers two layers two layers two layers opaque (visual) supernatant with floccules 3 Redispersibility redispersible redispersible redispersible redispersible redispersible 4 pH 5.74 5.75 5.75 5.78 5.76 5 Particle 3.86 ± 2.86 3.57 ± 2.44 3.46 ± 2.58 3.76 ± 2.74 3.78 ± 2.68 size (μm) Observations T = 14 days, 40° C./75% RH 1 Sedimentation 0.74 0.78 0.39 0.33 0.60 Coefficient 2 Appearance clear clear clear clear clear (visual) supernatant supernatant supernatant supernatant supernatant with with with with with floccules floccules floccules, floccules, floccules, an opaque an opaque an opaque flocculation flocculation flocculation layer between layer between layer between clear clear clear supernatant supernatant supernatant and and and sedimentation sedimentation sedimentation 3 Redispersibility redispersible redispersible redispersible; redispersible; redispersible curdy, loose curdy, loose sedimentation sedimentation right right away after away after shaking shaking 4 pH 5.32 5.32 5.40 5.40 5.32 5 Particle 3.93 ± 3.00 3.86 ± 3.08 3.94 ± 3.03 3.96 ± 3.10 3.83 ± 2.72 size (μm)

TABLE 10 Observations for freeze-thawing cycles of −10° C. (3-day) and RT (3-day) DS-54 DS-55 DS-56 DS-57 DS-58 Formulation ID Methocel F50 Methocel E50 Methocel A4MP MC, 400 cps Klucel JF Polymer 3% w/v 3% w/v 0.5% w/v 0.5%. w/v 3% w/v Observations after Freeze-Thawing Cycle: storage at −10° C. for 3 days followed by at RT for 3 days Sedimentation 1 Cycle 0.96 0.96 0.48 0.34 0.66 Coefficient 2 Cycle 0.96 0.96 0.50 0.34 0.67 3 Cycle 0.96 0.96 0.50 0.34 0.54 4 Cycle 0.96 0.96 0.49 0.30 0.70 5 Cycle 0.96 0.96 0.49 0.38 0.79 Appearance (visual) 1 Cycle uniform uniform clear supernatant sedimentation opaque with floccules, two layers, supernatant a thin opaque opaque with floccules flocculation layer supernatant between clear with floccules supernatant and sedimentation 2 Cycle sedimentation uniform clear sedimentation opaque two layers supernatant two layers, supernatant opaque with floccules supernatant with floccules 3 Cycle sedimentation uniform clear supernatant, opaque to clear A thin clear two layers sedimentation supernatant, supernatant two layers sedimentation on top, a two layers thick opaque flocculation layer between clear supernatant and sedimentation 4 Cycle uniform uniform clear clear supernatant, opaque supernatant a milky supernatant flocculation with floccules layer between clear supernatant and sedimentation 5 Cycle uniform uniform clear clear supernatant, opaque supernatant a milky supernatant flocculation with floccules layer between clear supernatant and sedimentation, sedimentation two layers Redispersibility 1 Cycle redispersible redispersible redispersible; redispersible redispersible sedimentation occurs at 10 min after shaking 2 Cycle redispersible redispersible redispersible; redispersible redispersible sedimentation occurs at 10 min after shaking 3 Cycle redispersible redispersible redispersible; redispersible; redispersible sedimentation sedimentation occurs at 10 min occurs at 10 min alter shaking, after shaking sedimentation appears loose and curdy 4 Cycle redispersible redispersible redispersible: redispersible; redispersible sedimentation sedimentation occurs at 10 min occurs at 10 min after shaking, after shaking sedimentation appears loose and curdy 5 Cycle redispersible redispersible redispersible; redispersible; redispersible sedimentation sedimentation occurs at 10 min occurs at 10 min after shaking, after shaking sedimentation appears loose and curdy pH 1 Cycle 5.66 5.66 5.69 5.70 5.64 2 Cycle 5.62 5.63 5.66 5.69 5.57 3 Cycle 5.60 5.58 5.62 5.66 5.52 4 Cycle 5.61 5.56 5.60 5.61 5.54 5 Cycle 5.65 5.67 5.62 5.59 5.50 Particle 1 Cycle 3.89 ± 3.33 3.88 ± 3.21 3.86 ± 2.81 3.92 ± 3.20 3.82 ± 2.46 size 2 Cycle 3.94 ± 2.87 3.98 ± 2.97 3.97 ± 3.09 4.05 ± 3.25 3.99 ± 2.87 (μm) 3 Cycle 4.02 ± 3.25 4.08 ± 3.83 4.12 ± 3.15 4.06 ± 3.09 4.07 ± 3.69 4 Cycle 4.21 ± 3.07 4.27 ± 3.01 4.26 ± 3.29 4.25 ± 2.78 4.26 ± 2.86 5 Cycle 4.31 ± 3.04 4.29 ± 2.85 4.28 ± 2.99 4.32 ± 3.32 4.30 ± 3.30

TABLE 11 Observations for Freeze-Thaw cycles of RT (3-day) and 2-8° C. (3-day) DS-54 DS-55 DS-56 DS-57 DS-58 Formulation ID Methocel F50 Methocel E50 Methocel A4MP MC. 400 cps Klucel JF Polymer 3% w/v 3% w/v 0.5% w/v 0.5% w/v 3% w/v Observations after Thawing-freeze Cycle: storage at RT for 3 days followed by at 2-8° C. for 3 days Sedimentation Coellicient 1 Cycle 0.97 0.97 0.53 0.96 0.62 2 Cycle 0.96 0.96 0.55 0.24 0.77 3 Cycle 0.96 0.96 0.53 0.23 0.70 4 Cycle 0.96 0.96 0.54 0.53 0.78 5 Cycle 0.94 0.90 0.52 0.51 0.56 Appearance (visual) 1 Cycle sedimentation sedimentation clear supernatant, sedimentation opaque two layers two layers a thin opaque two layers supernatant flocculation layer with between, clear floccules supernatant and sedimentation, sedimentation two layers 2 Cycle sedimentation sedimentation clear supernatant sedimentation opaque two layers two layers two layers, supernatant milky with supernatant floccules with flocculus 3 Cycle sedimentation sedimentation clear supernatant An opaque opaque two layers two layers supernatant supernatant on top, with a thick milky floccules flocculation layer between opaque supernatant and sedimentation, sedimentation two layers 4 Cycle sedimentation sedimentation two clear supernatant clear supernatant opaque two layers layers sedimentation supernatant two layers with floccules 5 Cycle sedimentation clear to opaque clear supernatant clear supernatant A thin clear two layers supernatant, sedimentation supernatant on sedimentation two top, a thick two layers layers opaque flocculation layer between clear supernatant and sedimentation Redispersibility 1 Cycle redispersible redispersible redispersible; redispersible redispersible sedimentation occurs at 10 min after shaking 2 Cycle redispersible redispersible redispersible: redispersible redispersible sedimentation occurs at 10 min after shaking 3 Cycle redispersible redispersible redispersible; redispersible redispersible sedimentation occurs at 10 min after shaking 4 Cycle redispersible redispersible redispersible; redispersible; redispersible sedimentation sedimentation occurs occurs at 30 min at 10 min after shaking after shaking, sedimentation appears loose and curdy 5 Cycle redispersible redispersible redispersible; redispersible; redispersible sedimentation sedimentation occurs at 10 min occurs at 10 min after shaking, after shaking sedimentation appears loose and curdy pH 1 Cycle 5.70 5.77 5.71 5.70 5.63 2 Cycle 5.67 5.68 5.67 5.73 5.61 3 Cycle 5.61 5.58 5.70 5.65 5.53 4 Cycle 5.57 5.58 5.62 5.64 5.55 5 Cycle 5.62 5.58 5.57 5.62 5.47 Particle 1 Cycle 4.10 ± 2.63 4.09 ± 3.04 3.96 ± 2.41 4.09 ± 3.14 4.08 ± 2.76 size (μm) 2 Cycle 4.31 ± 3.66 4.37 ± 3.29 4.13 ± 2.77 4.22 ± 2.45 4.16 ± 2.58 3 Cycle 4.36 ± 3.43 4.37 ± 3.01 4.36 ± 3.20 4.41 ± 3.42 4.41 ± 3.11 4 Cycle 4.44 ± 3.3 1 4.38 ± 3.19 4.47 ± 3.05 4.48 ± 3.23 4.46 ± 3.00 5 Cycle 4.47 ± 2.87 4.49 ± 2.98 4.47 ± 3.28 4.50 ± 3.06 4.48 ± 2.92

It was observed that suspensions with 3% Methocel F50 or 3% Methocel E50 as suspending agents showed good stability for 14 days and after 5 freeze-thawing cycles, but slow reconstitution rates were observed when dispersing blends in purified water.

Suspensions using 0.5% Methocel A4MP as suspending agent showed loose and curdy sedimentation during stability study, indicating incompatibility.

However, 0.5% Methylcellulose (400 cps) or 3% Klucel JF Pharm as suspending agents showed good reconstitution rate and acceptable stability and therefore could be used as alternative suspending agents for the target formulation.

Example 6: Optimization of Suspending Anent Concentration for Dispersibility Study (Using Simethicone Granular MED-342)

According to the observations of DS-54 to DS-58, concentrations of Methocel F50, Methocel E50, and Klucel JF Pharm were decreased for better dispersibility, while concentration of Methylcellulose 400 cps was increased for a balance between dispersibility and viscosity. Simethicone in the formulations was changed to the granular solid form (MED-342), which simplifies the process by avoiding adsorbing liquid simethicone on lactose. The compositions are shown in Table 12.

TABLE 12 Composition of blends using Simethicone granular solid Quantity per unit (mg) S.# Ingredients DS-54 DS-55 DS-57 DS-58 DS-63 DS-64 DS-65 DS-66 DS-67 DS-68 DS-69 DS-70 1 Tecovirimat Granules 346.50 346.50 346.50 346.50 346.50 346.50 346.50 346.50 346.50 346.50 346.50 346.50 2 Sucralose, NF 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 3 Simethicone 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 granular solid, USP (MED-342) 4 Lactose Monohydrate, 483.50 483.50 608.50 483.50 508.50 508.50 583.50 508.50 533.50 533.50 558.50 533.50 NF (SuperTab 11SD) 5 Hypromellose 150.00 — — — 125.00 — — — 100.00 — — — (Methocel F 50) Hypromellose 150.00 — — — 125.00 — — — 100.00 — — (Methocel E 50) Methyl Cellulose, — — 25.00 — — — 50.00 — — — 75.00 — 400 cps, USP Hydroxypropyl — — — 150.00 — — — 125.00 — — — 100.00 cellulose (Klucel JF Pharm), NF 6 Purified water, — — — — — — — — — — — — USP, Q.S. to 5 mL Total 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00 1000.00

In general, the formulation procedures include:

-   -   1. blending of Tecovirimat granules and simethicone granular         solid (MED-342), then passing through Quadro Comil equipped with         2B039R03125173*(991) screen;     -   2. weighing of quantity equivalent to 40 g of         Simethicone-Tecovirimat granules blend and mixing geometrically         with other components;     -   3. passing again of the blend through Quadro Comil using         2B039R03125173*(991) screen and     -   4. dispersing of 1 dose in purified water to make Q.S. to 5 mL,         followed by evaluation of dispersibility and dissolution (Table         13).

TABLE 13 Observation of reconstitution and dissolution Formulation ID S.# Properties DS-54 DS-55 DS-57 DS-58 1 Chunks Big Big None Very remaining chunks chunks small at bottom chunks after shaking Dissolution Time % SD % SD % SD % SD 2 (n = 3) (mins) Released Released Released Released 5 78.5 4.5 85.3 2.3 83.6 2.6 72.7 1.5 10 76.6 5.7 83.7 1.9 82.4 1.9 81.8 1.5 15 76.0 6.7 84.2 1.6 82.5 1.1 83.2 1.6 30 76.1 6.3 84.2 2.0 84.0 0.2 85.8 0.8 45 76.1 6.2 84.0 2.0 83.7 1.1 86.7 2.3 Formulation ID S.# Properties DS-63 DS-64 DS-65 DS-66 DS-67 DS-68 DS-69 DS-70 1 Chunks remaining at Mediun Medium Small None Small Small Small None bottom after shaking chunks chunks chunks chunks chunks chunks

The % ST-246 is shown in FIG. 1 .

It was observed that when concentrations of Methocel F50 and Methocel E50 decreased to 2.0% w/v (DS-67 and DS-68), there were still chunks remaining after shaking manually. Hydration rates of these two polymers are fast such that the gel layers developed inhibit the wetting of inside materials, leading to fish eyes and bad dispersibility. Concentration of 0.5-1.0% w/v Methylcellulose 400 cps and 2.0-2.5% w/v Klucel JF Pharm can reach a balance between good dispersibility and viscosity.

Example 7: Evaluation of a Combination of Suspending Agents

Combinations of suspending agents were used for dissolution study. Compositions arc given in Table 14. The Target formulation using Avicel CL-611 as a suspending agent exhibits floating in the form of lumps in dissolution test.

TABLE 14 Composition of solid blends using combination of suspending agents Quantity per unit (ng) Prototype 1 Prototype 2 Prototype 3 Prototype 4 S.# Ingredients (DS-59) (DS-60) (DS-61) (DS-62) Tecovirimat Granules 346.50 346.50 346.50 346.50 2 Simethicone granular 10.00 10.00 10.00 10.00 solid, USP (MED-342) 3 Lactose Monohydrate, NF 328.50 348.50 373.50 370.50 (SuperTab 11SD) 4 Avicel CL-611, NF 50.00 25.00 5 Methyl Cellulose, 400 cps, 15.00 20.00 15.00 20.00 USP 6 Xantural 75 — — 5.00 3.00 7 Purified water, USP, — — — — Q.S. to 5 mL Total 750.00 750.00 750.00 750.00

The formulation procedures was as follows;

-   -   1. blending of Tecovirimat granules and Simethicone granular         solid (MED-342), then passing through Quadro Comil equipped with         213039R03125173*(991) screen;     -   2. weighing of the quantity equivalent to 30 units of         Simethicone-Tecovirimat blend and then geometric mixing with         other components; shaking and mixing of blend in a zip-lock bag;     -   3. dispersing of 1 dose in purified water to make Q.S. to 5 mL         for dissolution test (Table 15).

TABLE 15 Dissolution of suspensions using combination of suspending agents Formulation ID Prototype 1 Prototype 2 Prototype 3 Prototype 4 S.# Properties (DS-59) (DS-60) (DS-61) (DS-62) 1 Dispersibility Small chunks Small chunks Small chunks Small chunks remaining after remaining after remaining after remaining after shaking shaking shaking shaking 2 Viscosity Good viscosity Watery Watery Watery 3 Dissolution Instant dispersion Instant dispersion Gel clumps Gel clumps with formation of with formation of coarse particulates line particulates

Example 8: Optimizing Anti-Foaming Agent and Viscosity

The suspensions were optimized for defoaming and viscosity of suspension by changing the level of simethicone solid granular and methylcellulose 400 cps in reference formulation DS-60. The methylcellulose 400 cps was replaced with Klucel JF Pharm and formulated to test the effect on foaminess. The compositions are given in Table 16.

TABLE 16 Composition of DS-60A to DS-60E and DS-71 Quantity per unit (mg) S.# Ingredients DS-60A DS-60B DS-60C DS-60D DS-60E DS-71 1 Tecovirimat Granules 346.50 346.50 346.50 346.50 346.50 346.50 2 Simethicone granular 16.67 25.00 16.67 16.67 16.67 16.67 solid, USP (MED-342) 3 Lactose Monohydrate, 341.83 333.50 336.83 331.83 331.83 341.83 NF (SuperTab 11SD) 4 Avicel CL-611, NF 25.00 25.00 25.00 25.00 25.00 25.00 Methyl Cellulose. 20.00 20.00 25.00 30.00 37.50 — 400 cps, USP Hydroxypropyl cellulose — — — — — 20.00 (Klucel JF Pharm), NF 5 Purified water, — — — — — — USP, Q.S. to 5 mL Total 750.00 750.00 750.00 750.00 757.50 750.00

The formulation procedures included

-   -   1. geometric mixing of quantity equivalent to 30 units of         lactose monohydrate and simethicone (MED-342), then geometric         mixing with other components;     -   2. passing of the blend through Quadro Comil equipped with         2B039R03125173*(991) screen and     -   3. dispersing of 1 dose in purified water to make Q.S. to 5 mL         to test foaminess and viscosity (Table 17).

TABLE 17 Observation of foaminess and viscosity of DS-60A to DS-60E and DS-71 Formulation ID S.# Properties DS-60A DS-60B DS-60C DS-60D DS-60E DS-71 1 Dispersibility Easy to Easy to Easy to Easy to Small chunks Easy to disperse, disperse, disperse, disperse, remaining disperse, no chunks no chunks no chunks no chunks after no chunks remaining remaining remaining remaining shaking remaining 2 Foaminess Less foam Decreased Decreased Decreased Decreased Less foam than foam foam foam foam than DS-60 DS-60A 3 Viscosity Watery Watery Watety Watery Good Watery viscosity

It was observed that the level of 16.67-25 mg per unit of Simethicone (MED-342) attains a good anti-foaming effect. The replacement of Klucel F Pharm with Methylcellulose 400 cps also decreases foaminess. Good viscosity in suspension was observed when Methylcellulose 400 cps level reached 0.75% w/v.

Example 9: Methylcellulose (400 cps and 15 cps) Combination as Suspending Agents

The level of Methylcellulose 15 cps was adjusted for better dispersibility. Compositions are given in Table 18.

TABLE 18 Composition of DS-72 to DS-74 Quantity per unit (mg) S.# Ingredients DS-72 DS-73 DS-74 1 Tecovirimat Granules 346.50 346.50 346.50 2 Simethicone granular solid, USP 16.67 16.67 16.67 (MED-342) 3 Lactose Monohydrate, NF 349.33 349.33 349.33 (SuperTab 11SD) 4 Methyl Cellulose, 400 cps, USP 37.50 33.50 30.00 Methyl Cellulose, 15 cps, USP — 4.00 7.50 5 Purified water, USP, — — — Q.S. to 5 mL Total 750.00 750.00 750.00

The formulation procedure included

-   -   1. geometric mixing of Tecovirimat granules, lactose monohydrate         and Simethicone (MED-342) and passing of blend through Quadro         Comil equipped with 2B039R03125173*(991) screen;     -   2. weighing of quantity equivalent to 10 units of blend and then         geometric mixing with polymer(s) and     -   3. dispersing of 1 dose in purified water to make Q.S. to 5 ml,         to test dispersibility.     -   It was observed that all three formulations were easy to         disperse with no chunks remaining after shaking. With decreased         level of Methylcellulose 400 cps in formulation, suspension was         more watery, suggesting it's better to keep Methylcellulose 400         cps more than 0.75% w/v.

Example 10: Optimizing levels of Methylcellulose 15 cps and Simethicone in Methylcellulose Combination for Rapid Hydration

Methylcellulose 400 cps concentration was kept as 1.0% w/v, and the amount of Methylcellulose 15 cps was adjusted for better dispersibility/hydration and the level of Simethicone (MED-342) adjusted to investigate the anti-foaming effect. Compositions are given in Table 19. Total blends were decreased to 500 mg per unit.

TABLE 19 Composition of DS-75 to DS-82 Quantity per unit (mg) S.# Ingredients DS-75 DS-76 DS-77 DS-78 DS-79 DS-80 DS-81 DS-82 1 Tecovirimat Granules 346.50 346.50 346.50 346.50 346.50 346.50 346.50 346.50 2 Sucralose, NF 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 3 Simethicone granular 20.00 20.00 20.00 20.00 20.00 25.00 30.00 35.00 solid, USP (MED-342) 4 Lactose Monohydrate, 43.50 63.50 53.50 43.50 58.50 53.50 53.50 53.50 NF (SuperTab 11SD) 5 Methyl Cellulose, 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 400 cps, USP Methyl Cellulose, — 5.00 15.00 25.00 10.00 15.00 15.00 15.00 15 cps, USP 6 Strawberry flavor, 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 #133.16296 7 Purified water, — — — — — — — — USP, Q.S. to 5 mL Total 475.00 500.00 500.00 500.00 500.00 505.00 510.00 515.00

The formulation procedure was as follows;

-   -   1. geometric mixing of quantity equivalent to 100 units of         Tecovirimat granules, sucralose, lactose monohydrate,         Simethicone (MED-342) and Methylcellulose 400 cps in DS-75, then         passing of blend through Quadro Comil equipped with         2B039R03125173*(991) screen;     -   2. for DS-75, weigh quantity equivalent to 50 units of blend and         then geometric mixing with strawberry flavor;     -   3. for DS-77, weigh quantity equivalent to 30 units of blend and         then geometric mixing with strawberry flavor, Methylcellulose 15         cps, and lactose monohydrate;     -   4. for DS-76 to DS-79, weigh quantity equivalent to 10 units of         DS-75 and then geometric mixing with other components.     -   5. for DS-80 to DS-82, weigh quantity equivalent to 5 units of         DS-77 and then geometric mixing with other components and     -   6. dispersing of 1 dose in purified water to make Q.S. to 5 mL         to test dispersibility, foaminess and sedimentation (Table 20).

TABLE 20 Observation of suspensions of DS-75 to DS-82 Formulation ID S.# Properties DS-75 DS-76 DS-77 DS-78 DS-79 DS-80 DS-81 DS-82 1 Dispersibility small very no no no big big big (chunks remaining at chunks tiny chunks chunks chunks chunks chunks chunks bottom after shaking) chunk 2 Settlement/ T = 0 No sedimentation. Foam is similar in all formulations foaminess T = 30 min No sedimentation. Individual bubbles are smaller in DS-80, DS-81, DS-82 T = 1 hr No sedimentation. Individual bubbles are smaller in DS-80, DS-81, DS-82 Quantity of foam is less inDS-80, DS-81, DS-82 T = 2 hr No sedimentation. A very thin layer of foam in DS-80 and DS-81. No foam in DS-82. T = 17 hr Foaminess No foam in all formulations Sedimentation 0.82 0.84 0.86 0.86 0.86 0.86 0.82 0.82 coefficient Second 4 4 4 4 4 4 5 5 layer (mm)

It was observed that methylcellulose 15 cps level of 10-25 mg per Tecovirimat dosage unit can lead to good dispersibility/hydration. There was no significant difference in foaminess of suspensions initially and after 17 hours of reconstitution in formations with Simethicone level of 20-35 mg per unit. The big chunks in formulation with 25-35 mg Simethicone per unit may be caused by Simethicone agglomeration, suggesting that it is advantageous to keep Simethicone as 20 mg per unit. All formulations showed good viscosity with 1% w/v Methylcellulose 400 cps.

Example 11: Scale-Up of the Optimized Compositions

Scale-up batches using methylcellulose (400 cps) and Klucel JXF Pharm as suspending agents were prepared and evaluated. Compositions are given in Table 21.

TABLE 21 Composition of Scale-Up batches Quantity per unit (mg) Goal: Using Methylcellulose (400 cps and 15 cps) as a suspending Goal: Using Hydroxypropyl Cellulose agent (Klucel JXF Pharm) as a suspending (500 g scale). agent (500 g scale). Batch: FSIG- Batch: FSIG- Batch: FSIG- Batch: FSIG- 20140826-1 20140826-2 20141216-1 20141216-2 S. # Ingredients (DS-75) (DS-77) (DS-83) (DS-84) 1 Tecovirimat 346.49 346.49 346.50 346.50 Granulate 2 Lactose 66.01 51.01 93.00 — monohydrate, NF (SuperTab 11SD) 3 Methylcellulose, 50.00 50.00 — — 400 cps, USP 4 Methylcellulose, — 15.00 — — 15 cps, USP 5 Hydroxylpropyl — — 125.00 118.00 Cellulose (Klucel JXF Pham) 6 Sucralose, NF 10.00 10.00 10.00 10.00 7 Strawberry flavor, 5.00 5.00 — — #133.16296 8 Black cherry Nat — — 3.00 3.00 type flavor 9 Simethicone 20.00 20.00 20.00 20.00 Granular Solid (MED-342), USP 10 Magnesium 2.50 2.50 2.50 2.50 stearate, NF Total weight (mg) 500.00 500.00 600.00 500.00

The batch size of each composition was 0.500 kg. In general, the formulation procedure involved the following steps:

-   -   1. Sieving of the Tecovirimat granules and granular Simethicone         through Quadro Comil equipped with 2B039R03125173*(991) screen.     -   2. Sieving of the Tecovirimat granulate and granular Simethicone         through a #20 screen.     -   3. Sieving of lactose through a #20 screen, then addition of         Flavor on lactose with geometric mixing using spatula.     -   4. Sieving of polymer and sucralose through a #40 screen.     -   5. Blending of the Tecovirimat-Simethicone blend and other         extra-granular components in the V-blender for 15 minutes.     -   6. Passing of magnesium stearate through a #40 screen, then         addition as a lubricant to above milled blend and lubricate for         5 minutes.     -   7. Evaluation of the physicochemical properties of blend (Table         22).     -   8. Transfer of 10 doses of blend to a 100 cc glass bottle. Add         water Q.S. to 50 mL. Shake well to mix the content. Evaluate the         physicochemical properties of suspension (Table 21).     -   9. Packing of 20 doses of blend in Stick pack PAKVF2.5M Fin seal         pouches (part #25M0275FS06) Size 2.5 inch×6 inch. Heat-seal         properly. Prepare 15-20 pouches for stability/dissolution study         (Table 24).

TABLE 22 Physicochemical properties of blends of scale-up batches Batch: FSIG- Batch: FSIG- Batch: FSIG- Batch: FSIG- S# Property 20140826-1 20140826-2 20141216-1 20141216-2 1 Appearance White powder White powder White powder White powder 2 Flow of Lubricated Blend 24 26 26 28 (Flodex Orifice mm) 3 Bulk Density (g/cc) 0.541 0.520 0.505 0.468 Tap Density (g/cc) 0.693 0.667 0.640 0.607 Compressibility Index (%) 21.9 22.0 21.1 22.9 4 Granules Retained on Sieve 0.01 0.01 0.02 0.02 # 20 (opening size 0.850 mm) (%) Granules Retained on Sieve 1.85 2.22 3.29 3.52 # 30 (opening size 0.600 mm) (%) Granules Retained on Sieve 9.37 10.46 8.60 10.61 # 40 (opening size 0.425 mm) (%) Granules Retained on Sieve 8.64 9.72 10.72 12.48 # 50 (opening size 0.300 mm) (%) Granules Retained on Sieve 4.12 4.36 4.06 5.24 # 60 (opening size 0.250 mm) (%) Granules Retained on Sieve 10.53 11.84 12.33 12.29 # 80 (opening size 0.180 mm) (%) Retained on Pan (size 65.47 61.40 60.96 55.84 <0.180 mm) (%) Mean Size (mm) 0.106 0.119 0.121 0.139

TABLE 23 Physicochemical properties of suspensions of scale-up batches S# Property Batch: FSIG-20140826-1 Batch: FSIG-20140826-2 1 Reconstitution After manual shaking, After manual shaking, fish fish eyes were observed eye was observed at at 4 positions at only one position at bottom of bottle. bottom of bottle. 2 Appearance White dispersion White dispersion after reconstitution 3 pH of 5.98 6.00 suspension 4 Microscopic Particle size 3.16 ± 2.37 μm. Particle size 3.20 ± 2.63 μm. observation No agglomeration observed. No agglomeration observed. 5 Physical No phase separation or No phase separation or stability agglomeration. agglomeration. 6 Forced Redispersible Redispersible settling and redispersibility 7 Observation of 10 min 30 min 24 hr 10 min 30 min 24 hr sedimentation At 25° C. Sedimentation 1.00 1.00 1.00 1.00 1 00 1.00 coefficient Separation None None Second None None Second layer layer (29% (29% height) height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible At 5° C. Sedimentation 1.00 1.00 1.00 1.00 100 1.00 coefficient Separation None None Second None None Second layer layer (23% (20% height) height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible S# Property Batch: FSIG-20141216-1 Batch: FSIG-20141216-2 1 Reconstitution After manual shaking, After manual shaking, fish eyes were observed no fish eye was at 2 positions at observed, disperse bottom of bottle. very well. 2 Appearance White dispersion White dispersion after reconstitution 3 pH of 5.99 6.15 suspension 4 Microscopic Particle size 3.04 ± 2.11 μm. Particle size 3.13 ± 2.53 μm. observation No agglomeration observed. No agglomeration observed. 5 Physical No phase separation. Small No phase separation. Small stability agglomerations are observed agglomerations are observed when pouring out. when pouring out. 6 Forced Redispersible Redispersible settling and redispersibility 7 Observation of 10 min 30 min 24 hr 10 min 30 min 24 hr sedimentation At 25° C. Sedimentation 1.00 1.00 0.56 1.00 1.00 0.58 coefficient Separation None None None None None None Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible At 5° C. Sedimentation 1.00 1.00 0.89 1.00 1.00 0.88 coefficient Separation None None None None None None Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersble Redispersible

TABLE 24 Stability and dissolution of scale-up batches Batch: FSIG- Batch: FSIG- Batch: FSIG- Batch: FSIG- 20140820-1 20140826-2 201412145-1 20141216-2 S# Property (DS75) (DS77) (DS83) (DS84) 1 Dissolution Time % SD % SD % SD % SD (n = 6) (mins) Released Released Released Released 5 88.6 1.3 88.4 1.5 84.2 6.7 92.4 4.2 10 90.2 1.7 92.3 1.5 93.9 4.4 97.6 1.7 55 89.4 1.5 90.5 2.8 94.1 2.0 99.3 1.7 30 90.4 1.3 90.2 1.4 96.9 0.9 101.4 2.2 45 93.6 2.5 90.7 1.5 97.1 1.0 100.3 0.7

The % ST-246 released is shown in FIG. 2 .

Example 12: Effect of Particle Sizes of API on Formulation Properties

To study the effect of particle sizes of API on formulation performance properties, such as dissolution, use API of different particle sizes for granulation process. Compositions are given in Table 25.

TABLE 25 Composition of DS-85 to DS-87 using API of different particle sizes Quantity per unit (mg) Goal: Using API of different particle sizes for granulation process (288.6 g scale). Ref. DS- 77 (Batch # FSIG-20140826-2) Batch: FSIG-20150120-1 Batch: FSIG-20150120-2 Batch: FSIG-20150120-3 S. # Ingredients (DS-85) (DS-86) (DS-87) Intragranular Ingredients: 1 Tecovirimat monohydrate, 209.0 209.0 209.0 micronized using API Lot# SG-10C12- using API Lot# SG-10C12- using API Lot# SG-10C12- T1039 (Trial #2, d90-21.51 T1039 (Trial #3, d90-38.74 T1039 (Trial #4, d90-81.53 μm) μm) μm) 2 Colloidal silicon dioxide, NF 1.95 1.95 1.95 (Cabosil M5P) 3 Croscarmellose sodium, NF 31.32 31.32 31.32 (AcDiSol) 4 Lactose monohydrate, NF 33.15 33.15 33.15 (SuperTab 11SD) 5 Microcrystalline cellulose. NF 49.62 49.62 49.62 (Avicel PH 101) Intragranular Ingredients Total 325.04 325.04 325.04 Granulating Fluid: 6 Hypromellose, USP (Methocel E3 13.65 13.65 13.65 LV Prem.) 7 Sodium lauryl sulfate, NF 7.80 7.80 7.80 8 Purified water, USP* 170.1 170.1 170.1 Granulating Fluid Solids Total 21.45 21.45 21.45 Granulate Solids 346.49 346.49 346.49 Extragranular Ingredients: 9 Lactose monohydrate, NF 51.01 51.01 51.01 (SuperTab 11SD) 10 Methylcellulose, 50.0 50.0 50.0 400 cps, USP 11 Methylcellulose, 15.0 15.0 15.0 15 cps, USP 12 Sucralose, NF 10.0 10.0 10.0 13 Strawberry flavor, #133.16296 5.0 5.0 5.0 14 Simethicone Granular Solid 20.0 20.0 20.0 (MED-342), USP 15 Magnesium stearate, NF 2.5 2.5 2.5 Powder for Reconstitution Blend Total 500.00 500.00 500.00 *Removed during the drying process.

The batch size of each composition was 0.2886 Kg. Detailed experimental procedures and results of each trial formulation were recorded in the executed batch records. In general, the formulation procedure involved the following steps:

-   -   1. Passing of intragranular components through a #20 screen.     -   2. Mixing of intragranular components containing diluents,         disintegrant, in GMX-High Shear Granulator/Mixer (1 L bowl) at         impeller blade speed 460 rpm and chopper speed of 2000 rpm for 2         minutes.     -   3. Addition of granulating solution containing surfactant,         binder (7.1% w/w Hypromellose Methocel E3 solution) and mixing         with the intragranular components in GMX-High Shear         Granulator/Mixer at impeller blade speed 460 rpm and chopper         blade 2000 rpm for 8-10 minutes.     -   4. Addition of about 1.5 g water to rinse the container,         granulation for additional 2 minutes, recording of the visual         observation of the wet mixture.     -   5. Drying of wet granular mass using a Midi-Glatt fluid bed         dryer/processor at inlet temperature 35-40° C. until the loss on         drying (LOD) of the granules reached the range of 4.00-5.50%         w/w, following are the typical drying parameters.

Parameters Units Product Air Pressure (bar) 0.25-0.30 Inlet Air Temperature (° C.) 35 Filter Blowing Rate (Sec)  1 Product Temperature (° C.)-at end   20-21

-   -   6. Passing of the dried granules through Quadro Comil equipped         with 2R039R03125173*(991) screen.     -   7. Weighing of the granules, then recalculation and weighing of         extragranular ingredients.     -   8. Passing of the Tecovirimat granules and granular Simethicone         through Quadro Comil equipped with 2B039R03125173*(991) screen.     -   9. Passing of the Tecovirimat granulate and granular Simethicone         through a #20 screen.     -   10. Passing of lactose through a #20 screen and addition of         Flavor on lactose with geometric mixing using spatula.     -   11. Passing of polymer and sucralose through a #40 screen.     -   12. Blending of the Tecovirimat-Simethicone blend and other         extragranular components in the V-blender for 15 minutes.     -   13. Passing of magnesium stearate through a #40 screen, then         addition as a lubricant to above milled blend and lubricate for         5 minutes.     -   14. Evaluation of the physicochemical properties of blend (Table         26).     -   15. Transfer of 10 doses of blend to a 100 cc glass bottle. Add         water Q. S. to 50 mL. Shake well to mix the content. Evaluate         the physicochemical properties of suspension (Table 27).     -   16. Packing of 20 doses of blend in Stick pack PAKVF2.5M Fin         seal pouches (part #25M0275FS06); size 2.5 inch×6 inch.         Heat-seal properly. Prepare 3 pouches for dissolution study         (Table 28).

TABLE 26 Characterization of blends DS-85 to DS-87 Batch: FSIG- Batch: Batch: FSIG- 20150120-1 FSIG-20150120-2 20150120-3 S# Property (DS-85) (DS-86) (DS-87) 1 Appearance White powder White powder White powder 2 Flow of Lubricated Blend 24 24 24 (Flodex Orifice mm) 3 Bulk Density (g/cc) 0.454 0.436 0.426 Tap Density (g/cc) 0.605 0.590 0.568 Compressibility Index (%) 25.0 26.1 25.0 4 Granules Retained on Sieve # 20 0.02 0.02 0.02 (opening size 0.850 mm) (%) Granules Retained on Sieve # 30 8.03 4.84 2.04 (opening size 0.600 mm) (%) Granules Retained on Sieve # 40 18.50 18.50 8.81 (opening size 0.425 mm) (%) Granules Retained on Sieve # 50 14.86 12.11 10.99 (opening size 0.300 mm) (%) Granules Retained on Sieve # 60 5.32 3.60 6.14 (opening size 0.250 mm) (%) Granules Retained on Sieve # 80 37.04 28.28 38.65 (opening size 0.180 mm) (%) Retained on Pan (size <0.180 16.24 32.65 33.35 mm) (%) Mean Size (mm) 0.252 0.204 0.168

TABLE 27 Characterization of suspensions of DS-85 to DS-87 Batch: FSIG-20150120-1 Batch: FSIG-20150120-2 S# Property (DS-85) (DS-86) 1 Reconstitution After manual shaking, no fish eyes is After manual shaking, no fish eye is observed, disperse very well. observed, disperse very well. 2 Appearance after White dispersion White dispersion reconstitution 3 pH of suspension 6.11 6.10 4 Microscopic Particle size 4.10 ± 3.42 μm. No Particle size 4.40 ± 3.52 μm. No observation agglomeration observed. agglomeration observed. 5 Physical stability No phase separation or agglomeration. No phase separation or agglomeration. 6 Forced settling and Redispersible Redispersible redispersibility 7 Observation of 10 min 30 min 24 hr 10 min sedimentation At 25° C. Sedimentation 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None (22% height) Redispersibility Redispersible Redispersible Redispersible Redispersible At 5° C. Sedimentation 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None (22% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Batch: FSIG-20150120-2 Batch: FSIG-20150120-3 S# (DS-86) (DS-87) 1 After manual shaking, no fish eye is After manual shaking, no fish eye is observed, disperse very well. observed, disperse very well. 2 White dispersion White dispersion 3 6.10 6.12 4 Particle size 4.40 ± 3.52 μm. No Particle size 4.84 ± 4.22 μm. No agglomeration observed. agglomeration observed. 5 No phase separation or agglomeration. No phase separation or agglomeration. 6 Redispersible Redispersible 7 30 min 24 hr 10 min 30 min 24 hr At 25° C. 1.00 1.00 1.00 1.00 1.00 None Second layer None None Second layer (22% height) (26% height) Redispersible Redispersible Redispersible Redispersible Redispersible At 5° C. 1.00 1.00 1.00 1.00 1.00 None Second layer None None Second layer (25% height) (25% height) Redispersible Redispersible Redispersible Redispersible Redispersible

TABLE 28 Dissolution profile of DS-85 to DS-87 Property Batch: FSIG-20150120-1 Batch: FSIG-20150120-2 Batch: FSIG-20150120-3 Time (DS-85) (DS-86) (DS-87) S# (mins) % Released SD % Released SD % Released SD 1 Dissolution 5 72.5 1.6 58.8 1.5 36.0 1.2 (n = 6) 10 82.2 0.7 66.7 3.0 46.0 0.9 15 85.5 1.1 71.8 2.3 51.7 0.8 30 88.2 2.3 75.7 3.3 60.2 1.7 45 90.3 2.0 80.4 3.0 64.7 1.0

It was observed that DS-85 (API D90=21.51 μm) showed higher dissolution rate compared to DS-86 (API D90=38.74 μm) and DS-87 (API D90=81.53 μm). The particle size of the Tecovirimat monohydrate used for granulation is inversely proportional to the dissolution rate. Smaller particle API batches showed higher dissolution rate as; DS-85>DS-86>DS-87 (see FIG. 3 ).

Example 13: Optimization of Blending and Lubrication Time Tecovirimat Monohydrate Powder for Reconstitution

To study the effect of blend/lubrication time on blend uniformity and dissolution, sample where taken at different time points during a blending range of 10-25 minutes and a lubrication of 3-10 minutes. Composition is given in Table 29.

TABLE 29 Composition of DS-88 Quantity per unit (mg) Goal: Blend or lube time DOE study (500 g scale). Ref. DS-75 (Batch # FSIG-20140826-1) Batch: FSIG-20150317-1 S. # Ingredients (DS-88) 1 Tecovirimat Granulate 346.49 2 Lactose monohydrate, NF 66.01 (SuperTab 11SD) 3 Methylcellulose, 400 cps, 50.00 USP 4 Sucralose, NF 10.00 5 Strawberry flavor, 5.00 #133.16296 6 Simethicone Granular Solid 20.00 (MED-342), USP 7 Magnesium stearate, NF 2.50 Total weight (mg) 500.00

The batch size was 0.500 Kg. In general, the formulation procedure involved the following steps:

-   -   1. Passing of the Tecovirimat granules and granular Simethicone         through Quadro Comil equipped with 2B039R03125173*(991) screen;     -   2. Passing of the Tecovirimat granulate and granular Simethicone         through a #20 screen;     -   3. Passing of lactose through a #20 screen, then addition of         Flavor on lactose with geometric mixing using spatula;     -   4. Passing of polymer and sucralose through a #40 screen;     -   5. Blending of the Tecovirimat-Simethicone blend and other         extragranular components in the V-blender, taking a 10 g sample         at 10, 15, and 20 minutes. Halt the process at 25 minutes and         repeat sampling;     -   6. Passing of magnesium stearate through a #40 screen, then         addition of 2.3 g as a lubricant to the remaining blend for         lubrication. Take a 10 g sample at 3, 5, and 7.5 minutes. Final         lubrication time is 10 minutes and repeat sampling;     -   7. Evaluation of the physicochemical properties of blend (Table         30);     -   8. Transfer of 10 doses of blend to a 100 cc glass bottle. Add         water Q. S. to 50 mL. Shake well to mix the content. Evaluate         the physicochemical properties of suspension (Table 31);     -   9. Addition of Q.S. purified water to 10 g samples at different         blending or lube time points to make 100 mL, then stirring well         for tests of reconstitution and dissolution (Table 32A and 32         B).

TABLE 30 Characterization of Blend DS-88 Batch: FSIG- 20150317-1 S# Property (DS-88) 1 Appearance White powder 2 Flow of Lubricated Blend (Flodex 24 Orifice mm) 3 Bulk Density (g/cc) 0.518 Tap Density (g/cc) 0.700 Compressibility Index (%) 26.0 4 Granules Retained on Sieve # 20 0.01 (opening size 0.850 mm) (%) Granules Retained on Sieve # 30 4.09 (opening size 0.600 mm) (%) Granules Retained on Sieve # 40 10.36 (opening size 0.425 mm) (%) Granules Retained on Sieve # 50 9.20 (opening size 0.300 mm) (%) Granules Retained on Sieve # 60 4.03 (opening size 0.250 mm) (%) Granules Retained on Sieve # 80 14.76 (opening size 0.180 mm) (%) Retained on Pan (size <0.180 mm) 57.55 (%) Mean Size (mm) 0.133

TABLE 31 Characterization of suspension of DS-88 Batch: FSIG-20150317-1 S# Property (DS-88) 1 Reconstitution After manual shaking, 1 fish eye is observed at bottom of bottle. 2 Appearance after White dispersion reconstitution 3 pH of suspension 6.13 4 Microscopic observation Particle size 3.28 + 2.72 μm. No agglomeration observed. 5 Physical stability No phase separation or agglomeration. 6 Forced settling and Redispersible redispersibility 7 Observation of sedimentation 10 min 30 min 24 hr At 25° C. Sedimentation coefficient 1.00 1.00 1.00 Separation None None Second layer (22% height) Redispersibility Redispersible Redispersible Redispersible At 5° C. Sedimentation coefficient 1.00 1.00 1.00 Separation None None Second layer (20% height) Redispersibility Redispersible Redispersible Redispersible

TABLE 32A Reconstitution and Dissolution of Samples at Different Blending Times (see FIG. 4) Batch: FSIG-20150317-1 (DS-88) Blending Blending Blending Blending 10 minutes 15 minutes 20 minutes 25 minutes S# Property (no lubricant) (no lubricant) (no lubricant) (no lubricant) 1 Reconstitution Tiny lumps, a little foam Tiny lumps, a little foam Tiny lumps, a little foam Tiny lumps, a little foam Time % % % % (mins) Released SD Released SD Released SD Released SD 2 Dissolution 5 90.6 1.0 92.5 2.4 90.2 1.1 92.3 1.2 (n = 6) 10 92.8 1.7 93.6 0.5 91.8 1.7 93.3 1.4 15 94.7 0.7 93.7 1.4 91.8 1.0 94.0 1.0 30 94.2 0.9 92.6 1.9 91.5 1.8 93.2 1.0 45 94.8 0.7 93.6 1.9 91.9 1.1 93.2 0.8

TABLE 32B Reconstitution and Dissolution of Samples at Different Lubrication Time (see FIG. 5) Batch: FSIG-20150317-1 (DS-88) Lubrication Lubrication Lubrication Lubrication 3 minutes 5 minutes 7.5 minutes 10 minutes S# Property (with lubricant) (with lubricant) (with lubricant) (with lubricant) 1 Reconstitution Tiny lumps, a little foam Tiny lumps, a little foam Tiny lumps, a little foam Tiny lumps, a little foam % Released SD % Released SD % Released SD % Released SD 2 Dissolution 93.6 1.6 92.9 1.1 90.0 1.1 95.5 1.3 (n = 6) 94.8 1.7 93.3 0.8 90.6 1.6 94.9 1.2 94.6 2.3 93.4 0.7 90.1 1.5 96.4 1.5 96.2 2.6 93.3 1.1 90.5 1.9 94.4 1.1 97.7 2.3 92.9 1.1 90.0 1.5 96.1 1.4

It was observed that all samples showed above 90% dissolution in 5 minutes, indicating that a blending range of 10-25 minutes and a lubrication range of 3-10 minutes have no significant effect on sample dissolution. Blending time and lubrication time is now fixed as 15 minutes and 5 minutes respectively as previous trials.

Example 31: Evaluation of Effect of High/Low Lubrication

To evaluate the effect of lubrication on +/−50% deviation of magnesium stearate level was used to test the effect of lubricant level on formulation physicochemical properties and dissolution. Compositions are given in Table 33.

TABLE 33 Composition of DS-89 and 90 Quantity per unit (mg) Goal: High/low lubricant DOE study (500 g scale). Ref. DS-75 (Batch # FSIG-20140826-1) Batch: FSIG-20150325-1 Batch: FSIG-20150325-2 (DS-89) (DS-90) 0.25% magnesium 0.75% magnesium S. # Ingredients stearate stearate 1 Tecovirimat Granulate 346.49 346.49 2 Lactose monohydrate, NF 67.26 64.76 (SuperTab 11SD) 3 Methylcellulose, 400 cps, USP 50.00 50.00 4 Sucralose, NF 10.00 10.00 5 Strawberry flavor, #133.16296 5.00 5.00 6 Simethicone Granular Solid (MED- 20.00 20.00 342), ESP 7 Magnesium stearate, NF 1.25 3.75 Total weight (mg) 500.00 500.00

The batch sire of each composition was 0.500 kg. In general, the formulation procedure involved the following steps:

-   -   1. Passing of the Tecovirimat granules and granular Simethicone         through Quadro Comil equipped with 2B3039R03125173*(991) screen.     -   2. Passing of the Tecovirimat granulate and granular Simethicone         through a #20 screen.     -   3. Passing of lactose through a #20 screen, then addition of         Flavor on lactose with geometric mixing using spatula.     -   4. Passing of polymer and sucralose through a #40 screen.     -   5. Blending of the Tecovirimat-Simethicone blend and other         extragranular components in the V-blender for 15 minutes.     -   6. Passing of magnesium stearate through a #40 screen, then         addition as a lubricant to above milled blend and lubricate for         5 minutes.     -   7. Evaluation of the physicochemical properties of blend (Table         34).     -   8. Transfer of 10 doses of blend to a 100 cc glass bottle. Add         water Q. S. to 50 mL. Shake well to mix the content. Evaluate         the physicochemical properties of suspension (Table 35).     -   9. Packing of 20 doses of blend in Stick pack PAKVF2.5M Fin seal         pouches (part #25M0275FS06); size 2.5 inch×6 inch. Heat-seal         properly. Prepare 3 pouches for dissolution study (Table 36).

TABLE 34 Characterization of blend DS-89 and DS-90 Batch: FSIG-20150325-1 Batch: FSIG- S# Property (DS-89) 20150325-2 (DS-90) 1 Appearance White powder White powder 2 Flow of Lubricated Blend (Flodex 24 24 Orifice mm) 3 Bulk Density (g/cc) 0.544 0.531 Tap Density (g/cc) 0.706 0.698 Compressibility Index (%) 22.9 23.9 4 Granules Retained on Sieve # 20 0.01 0.06 (opening size 0.850 mm) (%) Granules Retained on Sieve # 30 4.32 4.30 (opening size 0.600 mm) (%) Granules Retained on Sieve # 40 10.01 9.89 (opening size 0.425 mm) (%) Granules Retained on Sieve # 50 10.89 13.49 (opening size 0.300 mm) (%) Granules Retained on Sieve # 60 6.16 5.92 (opening size 0.250 mm) (%) Granules Retained on Sieve # 80 15.86 16.26 (opening size 0.180 mm) (%) Retained on Pan (size <0.180 mm) 52.74 50.08 (%) Mean Size (mm) 0.145 0.153

TABLE 35 Characterization of suspension of DS-89 and DS-90 Batch: FSIG-20150325-1 Batch: FSIG-20150325-2 S# Property (DS-89) (DS-90) 1 Reconstitution After manual shaking, no fish eye is After manual shaking, 2 fish eyes are observed, disperse very well. observed at bottom of bottle. 2 Appearance after White dispersion White dispersion reconstitution 3 pH of suspension 6.07 6.12 4 Microscopic Particle size 3.22 ± 2.91 μm. No Particle size 3.26 ± 3.00 μm. No observation agglomeration observed. agglomeration observed. 5 Physical stability No phase separation or agglomeration. No phase separation or agglomeration. 6 Forced settling Redispersible Redispersible and redispersibility 7 Observation of 10 min 30 min 24 hr 10 min 30 min 24 hr sedimentation At 25° C. Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None None Second layer (22% height) (23% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible At 5° C. Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None None Second layer (20% height) (36% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible

TABLE 36 Dissolution of DS-89 and DS-90 (see FIG. 6) Property Batch: FSIG-20150325-1 Batch: FSIG-20150325-2 Time (DS-89) (DS-90) S# (min) % Released SD % Released SD 1 Dissolution 5 91.2 0.7 94.8 2.2 (n = 6) 10 92.6 0.5 95.5 1.8 15 92.9 1.1 95.1 1.5 30 92.8 1.1 95.6 2.3 45 93.8 1.8 95.8 2.0

The quantity of magnesium stearate at 0.25% and 0.75% level of the formulation did not show any difference in physicochemical properties as well as dissolution of the product.

Example 15: Effect of Milling on Particle Size and Size Distribution of Tecovirimat Granules

The purpose is to study the effect of milling on particle size and size distribution of Tecovirimat granules. 100 g of Tecovirimat granules from Siga were used to test the size distribution. 110 g of Tecovirimat granules from the same Siga Lot # were passed through Quadra Comil equipped with 2B039R03125173*(991) screen, from which 100 g were weighed for size distribution test. The results are shown in Table 37.

TABLE 37 Particle size and size distribution of Tecovirimat Granules before/after milling Lot # Lot # 1401165 1401165 (before (after S# Property milling) milling) 1 Granules Retained on Sieve # 20 (opening 0.05 0.04 size 0.850 mm) (%) Granules Retained on Sieve # 30 (opening 6.38 4.47 size 0.600 mm) (%) Granules Retained on Sieve # 40 (opening 10.34 12.31 size 0.425 mm) (%) Granules Retained on Sieve # 50 (opening 10.80 11.64 size 0.300 mm) (%) Granules Retained on Sieve # 60 (opening 5.05 5.36 size 0.250 mm) (%) Granules Retained on Sieve # 80 (opening 8.48 8.55 size 0.180 mm) (%) Granules Retained on Sieve # 100 (opening 4.74 4.70 size 0.150 mm) (%) Retained on Pan (size <0.150 mm) (%) 54.17 52.93 Mean Size (mm) 0.150 0.150

It was observed that no significant different between the size distribution of Tecovirimat granules before or after milling.

Example 16: Evaluation of Pre-Dilution and as is Simethicone Before Mixing/Blending

Simethicone granular grade is currently prediluted/milled with Tecovirimat granules. The pre-dilution and no-dilution/as is Simethicone before mixing were compared, to establish the method of dilution that can be commercially reproduced at large scale. Compositions are given in Table 38.

TABLE 38 Composition of DS-91 and DS-92 Quantity per unit (mg) Goal: Simethicone pre-dilution or no-dilution (500 g scale). Ref. DS-75 (Batch # FSIG- 20140826-1) Batch: FSIG- Batch: FSIG- 20150407-1 20150407-2 (DS-91) (DS-92) pre-diluted undiluted S. # Ingredients Simethicone Simethicone 1 Tecovirimat Granulate 346.49 346.49 2 Lactose monohydrate, NF 66.01 66.01 (SuperTab 11SD) 3 Methylcellulose, 400 cps, USP 50.00 50.00 4 Sucralose, NF 10.00 10.00 5 Strawberry flavor, #133.16296 5.00 5.00 6 Simethicone Granular Solid (MED- 20.00 20.00 342), USP 7 Magnesium stearate, NF 2.50 2.50 Total weight (mg) 500.00 500.00

The batch size of each composition was 0.500 kg. In general, the formulation procedure involved the following steps:

-   -   1. For DS-91, passing of the Tecovirimat granules and granular         Simethicone through Quadro Comil equipped with         2B039R03125173*(991) screen, then passing of the Tecovirimat         granulate and granular Simethicone through a #20 screen;     -   2. For DS-92, passing of the Tecovirimat granulate through         Quadro Comil equipped with 2D039R03125173*(991) screen; then         passing of granular Simethicone through a #20 screen;     -   3. Passing of lactose through a #20 screen, then addition of         Flavor on lactose with geometric mixing using spatula;     -   4. Passing of polymer and sucralose through a #40 screen;     -   5. Blending of Tecovirimat granulate and all the extragranular         components in the V-blender for 15 minutes;     -   6. Passing of magnesium stearate through a #40 screen, then         addition as a lubricant to above milled blend and lubricate for         5 minutes;     -   7. Evaluation of the physicochemical properties of blend (Table         39);     -   8. Transfer of 10 doses of blend to a 100 cc glass bottle. Add         water Q. S. to 50 mL. Shake well to mix the content. Evaluate         the physicochemical properties of suspension (Table 40);     -   9. Packing of 20 doses of blend in Stick pack PAKVF2.5M Fin seal         pouches (part #25M0275FS06); size 2.5 inch×6 inch. Heat-seal         properly. Prepare 3 pouches for dissolution study (Table 41).

TABLE 39 Characterization of blend DS-91 and DS-92 Batch: FSIG- Batch: FSIG- 20150407-1 20150407-2 S# Property (DS-91) (DS-92) 1 Appearance White powder White powder 2 Flow of Lubricated Blend (Flodex 24 26 Orifice mm) 3 Bulk Density (g/cc) 0.533 0.525 Tap Density (g/cc) 0.701 0.700 Compressibility Index (%) 24.0 25.0 4 Granules Retained on Sieve # 20 0.03 0.06 (opening size 0.850 mm) (%) Granules Retained on Sieve # 30 4.26 4.06 (opening size 0.600 mm) (%) Granules Retained on Sieve # 40 10.10 10.49 (opening size 0.425 mm) (%) Granules Retained on Sieve # 50 10.87 10.11 (opening size 0.300 mm) (%) Granules Retained on Sieve # 60 3.50 4.18 (opening size 0.250 mm) (%) Granules Retained on Sieve # 80 12.92 13.80 (opening size 0.180 mm) (%) Retained on Pan (size <0.180 mm) 58.32 57.30 (%) Mean Size (mm) 0.133 0.135

TABLE 40 Physicochemical Properties of Suspension of DS-91 and DS-92 Batch: FSIG-20150407-1 Batch: FSIG-20150407-2 S# Property (DS-91) (DS-92) 1 Reconstitution After manual shaking, no fish eye is After manual shaking, no fish eye is observed, disperse very well. observed, disperse very well. 2 Appearance after White dispersion. White dispersion. reconstitution Foaminess similar to DS-92 Foaminess similar to DS-91. 3 pH of suspension 6.11 6.05 4 Microscopic Particle size 3.02 ± 2.03 μm. No Particle size 3.14 ± 2.47 μm. No observation agglomeration observed. agglomeration observed. 5 Physical stability No phase separation or agglomeration. No phase separation or agglomeration. 6 Forced settling Redispersible Redispersible and redispersibility 7 Observation of 10 min 30 min 24 hr 10 min 30 min 24 hr sedimentation At 25° C. Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None None Second layer (28% height) (33% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible At 5° C. Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None None Second layer (28% height) (33% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible

TABLE 41 Dissolution of DS-91 and DS-92 Property Batch: FSIG-20150407-1 Batch: FSIG-20150407-2 Time (DS-91) (DS-92) S# (min) % Released SD % Released SD 1 Dissolution 5 94.7 2.3 92.2 1.2 (n = 6) 10 94.6 1.9 91.3 1.2 15 94.2 1.2 91.6 1.3 30 93.8 1.1 90.6 1.2 45 94.9 2.4 91.0 4.0

It was observed that before blending when passing through the #20 screen. Simethicone with no-dilution partly stuck on sieve (FIGS. 8 A and B), while the pre-diluted and co-milled Simethicone and Tecovirimat granules passed through #20 screen easily (FIGS. 8 C and D). After sieve shaking fir size distribution analysis, big clumps from DS-92 remained on #20 screen (FIG. 9 ), indicating the formation of big Simethicone lumps when no-dilution before mixing.

FIG. 8 shows an observation when passing simethicone or co-milled simethicone-Tecovirimat granules through #20 screen. A and B: no-dilution simethicone stuck on screen. C and D: pre-diluted and co-milled simethicone-Tecovirimat granules passed screen easily without sticking.

FIG. 9 shows retained clumps on #20 screen after sieve shaking of 100 g DS-92.

Example 17: Evaluation of Simethicone from Alternate Source

Currently Simethicone Granular Solid (MED-342) from Nusil Technologies was used. An alternate source of Simethicone-Simethicone 50% Powder from AIC was used to test the effect on formulation. The pre-dilution and no-dilution of simethicone before mixing were compared. Compositions arm given in Table 41.

TABLE 41 Composition of DS-93 and DS-94 Quantity per unit (mg) Goal: Simethicone alternate source (500 g scale). Ref. DS-75 (Batch # FSIG-20140826-1) Batch: FSIG- Batch: FSIG- 20150421-1 20150421-2 (DS-93) (DS-94) pre-diluted Undiluted S. # Ingredients simethicone simethicone 1 Tecovirimat Granulate 346.49 346.49 2 Lactose monohydrate, 74.01 74.01 NF (SuperTab 11SD) 3 Methylcellulose, 400 50.00 50.00 cps, USP 4 Sucralose, NF 10.00 10.00 5 Strawberry flavor, 5.00 5.00 #133.16296 6 Simethicone 50% 12.00 12.00 Powder 7 Magnesium stearate, 2.50 2.50 NF Total weight (mg) 500.00 500.00

The batch size of each composition was 0.500 Kg. Detailed experimental procedures and results of each trial formulation were recorded in the executed batch records. In general, the formulation procedure involved the following steps:

-   -   1. For DS-93, passing of the Tecovirimat granules and         Simethicone powder through Quadro Comil equipped with         2D039R03125173*(991) screen, then passing of the Tecovirimat         granulate and Simethicone powder through a #20 screen;     -   2. For DS-94, passing of the Tecovirimat granulate through         Quadro Comil equipped with 2B039R03125173*(991) screen; then         passing of Simethicone powder through a #20 screen;     -   3. Passing of lactose through a #20 screen, then addition of         Flavor on lactose with geometric mixing using spatula;     -   4. Passing of polymer and sucralose through a #40 screen;     -   5. Blending of Tecovirimat granulate and all the extragranular         components in the V-blender for 15 minutes;     -   6. Passing of magnesium stearate through a #40 screen, then         addition as a lubricant to above milled blend and lubricate for         5 minutes;     -   7. Evaluation of the physicochemical properties of blend (Table         43);     -   8. Transfer of 10 doses of blend to a 100 cc glass bottle. Add         water Q. S. to 50 mL. Shake well to mix the content. Evaluate         the physicochemical properties of suspension (Table 44);     -   9. Packing of 20 doses of blend in Stick pack PAKVF2.5M Finseal         pouches (part #25M0275FS06); size 2.5 inch×6 inch. Heat-seal         properly. Prepare 3 pouches for dissolution study (Table 45).

TABLE 43 Characterization of blend DS-93 and DS-94 Batch: FSIG- Batch: FSIG- 20150421-1 20150421-2 S# Property (DS-93) (DS-94) 1 Appearance White powder White powder 2 Flow of Lubricated Blend (Flodex 20 20 Orifice mm) 3 Bulk Density (g/cc) 0.547 0.540 Tap Density (g/cc) 0.720 0.720 Compressibility Index (%) 24.0 25.0 4 Granules Retained on Sieve # 20 0.02 0.02 (opening size 0.850 mm) (%) Granules Retained on Sieve # 30 3.23 2.81 (opening size 0.600 mm) (%) Granules Retained on Sieve # 40 8.73 8.52 (opening size 0.425 mm) (%) Granules Retained on Sieve # 50 9.28 8.48 (opening size 0.300 mm) (%) Granules Retained on Sieve # 60 3.56 3.75 (opening size 0.250 min) (%) Granules Retained on Sieve # 80 13.96 11.28 (opening size 0.180 mm) ( %) Retained on Pan (size <0.180 mm) 61.23 65.15 (%) Mean Size (mm) 0.118 0.108

TABLE 44 Physicochemical properties of suspension of DS-93 and DS-94 Batch: FSIG-20150421-1 Batch: FSIG-20150421-2 S# Property (DS-93) (DS-94) 1 Reconstitution After manual shaking, no fish eye is After manual shaking, no fish eye is observed, disperse very well. observed, disperse very well. 2 Appearance after White dispersion, foaminess similar to White dispersion, foaminess similar to reconstitution DS-94, more foam than DS-91 and DS-92. DS-93, more foam than DS-91 and DS-92. 3 pH of suspension 6.11 6.07 4 Microscopic Particle size 3.40 ± 3.04 μm. No Particle size 3.46 ± 2.96 μm. No observation agglomeration observed. agglomeration observed. 5 Physical stability No phase separation or agglomeration. No phase separation or agglomeration. 6 Forced settling and Redispersible Redispersible redispersibility 7 Observation of 10 min 30 min 24 hr 10 min 30 min 24 hr sedimentation At 25° C. Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None None Second layer (26% height) (29% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible At 5° C. Sedimentation 1.00 1.00 1.00 1.00 1.00 1.00 coefficient Separation None None Second layer None None Second layer (25% height) (25% height) Redispersibility Redispersible Redispersible Redispersible Redispersible Redispersible Redispersible

TABLE 45 Dissolution of DS-93 and DS-94 Property Batch: FSIG-20150421-1 Batch: FSIG-20150421-2 Time (DS-93) (DS-94) S# (min) % Released SD % Released % Released 1 Dissolution 5 82.5 1.7 89.3 89.3 (n = 6) 10 84.7 1.4 86.8 86.8 15 85.4 0.7 86.9 86.9 30 86.5 1.1 88.2 88.2 45 86.2 1.9 88.4 88.4

It was observed that the undiluted simethicone 50% powder passed #20 screen easily without any sticking. The flowability of DS-93 and DS-94 using simethicone powder was better than that of previous batches using granular simethicone. The suspensions of DS-93 and DS-94 after reconstitution were similarly loamy, both containing much more foam than DS-91 and DS-92. Therefore the antifoaming effect of simethicone powder is not as efficient as that of granular simethicone.

Example 18: Taste Assessment of the Aqueous Pharmaceutical Suspension Formulations

The taste of the aqueous pharmaceutical suspension formulations according to the present invention is critically important to the successful oral administration.

Consequently the present invention provides a palatable powder for suspension dosage form of Tecovirimat which is suitable for pediatric and geriatric dosing

The following examples identify and quantify the sensory attributes (basic tastes, e.g., bitterness; aromatics and trigeminal effects) of a series of Tecovirimat aqueous suspensions.

Six experienced pharmaceutical sensory panelists were used to evaluate the above mentioned sensory attributes.

Samples were evaluated using the Flavor Profile method I of descriptive sensory analysis to identify, characterize and quantify the sensory attributes of the study samples. The Flavor Profile method was originally developed to assist The Upjohn Company in identifying off tastes in their gelatin capsules and provides a complete description of the sensory attributes of products. e.g., texture, aroma, taste, mouthfeel.

The method consists of formal procedures for describing and assessing the aroma (if appropriate) and flavor of a product in a reproducible manner. The Flavor Profile terms are shown in FIG. 11 .

Flavor Profile is used to identify the individual attributes of product flavor, including:

-   -   1. Basic tastes: sweet, sour, salty, and bitter;     -   2. Aromatics: volatile components perceived by the olfactory         system via the nasopharyngeal passage (retronasal) and     -   3. Feeling factors: numbing, cooling, warming, burning, drying,         oily, astringent, etc.

Flavor Profile also includes measures of the strength, or intensity, at which these character notes appear; the order in which the character notes appear; and a description of all sensations i.e. basic tastes, feeling factors, and aromatics remaining at specified time intervals after swallowing.

For some oral pharmaceuticals texture attributes such as hardness (chewable tablets) or particulates/grittiness (chewable tablets, sachets, suspensions) are also noted and assessed.

For oral pharmaceuticals, both the initial flavor quality and the aftertaste flavor quality are important to patient acceptability, and therefore it is important that each be evaluated. The initial flavor characteristics of the study products were evaluated during the first 10-20 seconds, and the aftertaste attributes were evaluated at multiple time intervals to 30 minutes as described below.

Sample Constitution and Taste Evaluation Protocols

The compounded Tecovirimat powder for suspension, micronized Tecovirimat API as well as tecovirimat granules taste assessment samples were constituted immediately prior to evaluations as follows:

-   -   1. The API-containing powder in an amber bottle was agitated to         ensure the powder moves around freely.     -   2. The purified (reverse osmosis) water premeasured was added to         each bottle containing the powder.     -   3. The bottles were mixed by hand for a few minutes. The         unflavored bottles were mixed vigorously and the flavored         bottles were mixed gently.     -   4. 5 mL samples were taken from each test formulation and         dispensed to each panelist for evaluation.

The panelists evaluated the constituted samples as follows:

-   -   1. The panelists cleansed their palates with spring water and         unsalted crackers.     -   2. 5 mL of sample was dispensed into individual 1-ounce plastic         cups using a graduated oral syringe and distributed to each         panelist.     -   3. Starting at the same time, the panelists poured the sample         directly in to their mouths, swished the contents around the         oral cavity for 10 seconds and expectorated. During this time         the panelists independently evaluated and recorded the initial         flavor characteristics.     -   4. The panelists then independently evaluated and recorded the         aftertaste characteristics at periodic intervals out to 30         minutes as flavor persisted.     -   5. The panelists recited their individual results and a         preliminary Flavor Profile was generated for the sample.     -   6. Steps 1 through 4 were repeated for a second evaluation of         the sample using the preliminary Flavor Profile from Step 5 as a         guide, with the panelists noting any necessary modifications.     -   7. The panelists recited their individual results and a final         Flavor Profile was developed for the sample.

Flavor Leadership Criteria

The flavor quality of the flavored drug product prototypes was interpreted using the relevant Flavor Leadership Criteria. Research reveals that the perennial sales leaders in many categories, including pharmaceuticals, have a set of sensory characteristics in common, which are known as the Flavor Leadership Criteria. The flavor profiles associated with products typically having the highest sales within a product category possess the following characteristics:

-   -   1. Have a quickly recognizable identifying flavor;     -   2. Develop full flavor that rapidly blends with and covers the         active and base characteristics;     -   3. Have no unpleasant mouth sensations (e.g., tongue sting);     -   4. Have no off-notes in the early impression or in the         aftertaste;     -   5. Have a short (or appropriate) aftertaste.

The concepts of Flavor Leadership were used to interpret the sensory analysis results and are described more fully below.

Immediate Impact of the Identifying Flavor.

Flavor Leaders exhibit an immediate impact of the identifying flavor. When a consumer tastes a product, the first character notes provide for product identification and set expectations for the remainder of the flavor experience. For example, many inexpensive chocolates have an initial waxy impression whereas high-quality chocolates are identified by an initial chocolate flavor and cocoa butter mouthfeel. Unfortunately for many oral pharmaceuticals, the first impression is bitterness or an aromatic off-note (e.g., green stemmy, musty, chalky) that many patients find unacceptable.

Rapid Development of Balanced, Full Flavor.

A well-blended flavor is key to product success. Flavor Leaders have a flavor that develops rapidly and is full bodied and well balanced. Blended flavor means that a complex body of underlying sensory impressions that are not separately identified support the expected character notes. For example. Coca-Cola® comprises hundreds of individual flavoring components that are hard to single out individually, the components are very well blended. Unlike most foods and beverages, the challenge for pharmaceuticals is to “blend away” the negative sensory attributes of the drug substance, while simultaneously minimizing the number of excipients in the formulation. Amplitude is an integrative measure of balance and fullness (see FIG. 11 ). It is an overall measure of the quality of the initial flavor and has been shown to correlate with palatability and patient acceptance. Amplitude of 1 is appropriate for most oral pharmaceuticals.

Compatible Mouthfeel Factors.

Flavor leader have a mouthfeel that is compatible with consumers' expectations. Many drug actives and excipients can cause trigeminal effects such as tongue sting or throat burn that may be unacceptable to patients and consumers. For example, a slight amount of mouth irritation would be acceptable in a citrus flavored formulation (“citrus rind mouth irritation”) but would be totally out-of-context in a bubblegum flavored formulation. Unexpected or stronger than expected mouthfeel factors can have an adverse effect on patient acceptability.

Examples of excipients that produce trigeminal effects include:

-   -   1. Methyl and propyl paraben (common preservatives in many oral         pharmaceuticals) produce a tongue sting and numbing that can be         unacceptable above a certain level.     -   2. Benzyl alcohol (solvent/preservative) produces both tongue         sting and bum.

No “Off-Flavors.”

Flavor leaders are notable for their consistent lack of off-flavors. An off-flavor is the appearance of an unexpected or unacceptable character note (off-note). For most oral pharmaceuticals the API is the principal source of off-notes, which can include basic tastes (e.g., bitter) and/or aromatics (e.g., sulfurous). Other sources of off-notes include excipients. e.g., paraben aromatics poor flavor systems that result in terpy, solventy, or perfumy off-notes, packaging interactions that “taint” or transfer of off-notes from the package to the product and “flavor scalping” or transfer (loss) of flavor aromatics from the product to the package.

Short (or Appropriate) Aftertaste.

The last impression i.e. the aftertaste is especially important to flavor quality. Aftertaste is caused by the persistence of one or a few character notes well after swallowing. For most products, a short, clean aftertaste is important. Products with a short, clean aftertaste encourage the consumer to take another bite or sip, and thereby to consume more of the product. For example, one of the major complaints about saccharin is its particularly long, bitter aftertaste and throat catch.

However, the goal for pharmaceuticals is patient compliance, not consumption. For many APIs, the aftertaste is most critical as many flavor systems provide adequate coverage in the early aftertaste but the beneficial effects quickly decrease, exposing the API.

As a general rule it is easier to mask a strongly bitter (or other) tasting API that “fades” quickly (steep decay curve) versus a moderately bitter API initially that lingers well into the aftertaste (flat decay curve). In any event, the challenge for the formulator is to mask the taste of the active throughout the duration of the aftertaste—be it 30 seconds or 30 minutes.

Drug Product

The study samples in Table 46 were compounded by Custom Medicine Pharmacenter, a compounding-only pharmacy in Beverly, Mass. following SIGA-approved batch records (logged formula worksheets). The Tecovirimat drug active was supplied by SIGA as bulk powder (granulated and micronized), and the excipients provided by SIGA approved suppliers.

TABLE 46 Study Formulations at 40 mg/mL Tecovirimat Concentration Form #3 Form #4 Form # 1 Form #2 (API (API (Strawberry (Cherry Granulated 200 Micronized 200 mg/ml) mg/ml) mg/ml) mg/ml) Batch Weight Batch Weight Batch Weight Batch Weight Ingredient Manufacturer Lot Number Expiry (g) (g) (g) (g) Tecovirimat, Granulate SIGA 1401165 Sep. 14, 2015 3.465 3.465 3.465 — Tracovirimat SIGA 9199001 Aug. 25, 2016 — — — 2.090 Monohydrate, Micronized Sucralose EMD K93441194 Mar. 8, 2016 0.100 0.100 — — Simethicone Granular NUSIL 66777 May 12, 2015 0.200 0.200 — — Solid Methocel, A4C DOW 2H22012N11 Aug. 22, 2015 0.500 0.500 — Strawberry Flavor, Bell Flavors 521145 Jun. 23, 2016 0.500 — — — 133.1529 Cherry Flavor, 23950 Virginia Dare T02198 Aug. 23, 2016 — 0.030 — — Lactose Monohyrdrate DFE Pharma 10700181 Feb. 28, 2015 0.685 0.705 — — Purified Water CMP — Dec. 31, 2015 47 mL 47 mL 47 mL 50 mL Volume Tasted 50 mL 50 mL 50 mL 50 mL

Taste Assessment Days

The four formulations shown in Table 46 were evaluated over a three-day period as necessary to ensure that the maximum daily exposure of 600 mg per day was not exceeded. The schedule was as follows:

Day 1:

Tecovirimat Formulation 3 (200 mg/5 mL)—Tasted twice Tecovirimat Formulation 4 (200 mg/5 mL)—Tasted once

Day 2:

Tecovirimat Formulation 4 (200 mg/5 mL)—Tasted once Tecovirimat Formulation 1 (200 mg/5 mL)—Tasted twice

Day 3:

Tecovirimat Formulation 1 (200 mg/5 mL)—Tasted once Tecovirimat Formulation 2 (200 mg/5 mL)—Tasted twice

Flavor Profile Results

The panelists evaluated the samples by the procedure outlined above. The results are summarized by formulation in tabular and graphical formats below. The tabular format contains the final Flavor Profile for the sample along with interpretation of the results using the Flavor Leadership Criteria.

The challenge for many oral pharmaceuticals is to mask the critical (“undesirable”) sensory characteristics of the active in the initial flavor and throughout the aftertaste.

To visualize the temporal sensory effects (aftertaste) it is useful to plot selected attribute intensities as a function of time. Thus, following each tabular summary is a graph. In each graph, the area above a slight intensity (>1) has been shaded. Negative sensory characteristics above this intensity are clearly perceptible to patients and are often found to be unacceptable.

To increase the likelihood of product acceptability the intensity of negative sensory characteristics should remain below this critical intensity throughout a product's flavor profile.

Tecovirimat—Formulation 3 (Granules)

Tecovirimat (200 mg/mL) Formulation #3 (Granule) is characterized by musty aromatic off notes, bitter basic taste and tannin/chalky mouth feels as shown in Table 47.

TABLE 47 Flavor Profile for Tecovirimat - Formulation 3 (Granules) Flavor Profile SIGA Tecovirimat Formulation #3 200 mg/mL (Granule) Initial 1 Min 3 Min 5 Min 10 Min 15 Min 20 Min 25 Min 30 Min Musty Aromatic 2 1½ 1 ½ — — — — — Sour ½ — — — — — — — — Bitter 1 1-1½ 1 ½ ½ ½ 0 — — Chalky Mouthfeel 1 1 ½-1 ½ — — — — — Tannin Mouthfeel 1½ 1-1½ 1 1 — — — — — Drying Mouthfeel ½ 1 1½ 1½ 1-1½ 1-1½ 1 ½ — Flavor Leadership Interpretation 1 - Aromatic Identity 2- Amplitude 3- Mouthfeel 4- Off-Notes 5-Aftertaste Not applicable Not applicable Chalky, tannin and Slight-to-moderate Lingering for unflavored for unflavored drying mouthfeels intensity bitterness bitterness, products products and moderate mouthfeels and intensity musty aromatic off-notes aromatic off-notes

The musty aromatic off-notes, bitterness and tannin mouthfeel of the Tecovirimat granules (Formulation #3) lingered at patient-perceptible levels (≥1) for about 3 minutes in the Aftertaste, see FIG. 12 .

Tecovirimat—Formulation 4 (Micronized)

Tecovirimat (200 mg/mL) Formulation #4 (micronized API) is characterized by aromatic offnotes (chalky, soapy/waxy), bitter basic taste and tannin/chalky mouthfeels, though generally lower in intensity than the API granules as shown in Table 48.

TABLE 48 Flavor Profile for Tecovirimat - Formulation 4 (Micronized) Flavor Profile SIGA Tecovirimat Formulation #4 200 mg/mL (Micronized API) Initial 1 Min 3 Min 5 Min 10 Min 15 Min 20 Min 25 Min 30 Min Chalky Aromatic 1-1½ 1 ½ — — — — — — Soapy/Waxy 1-1½ 1 ½ — — — — — — Aromatic Bitter 1 1-1½ ½-1 ½ ½ 0-½ — — Chalky Mouthfeel ½-1 1 1-1½ — — — — — — Tannin Mouthfeel 1 1 1 ½-1 ½ — — — — Drying Mouthfeel ½ 1 1 1 1 1 ½ 0-½ — Flavor Leadership Interpretation 1 - Aromatic Identity 2- Amplitude 3- Mouthfeel 4- Off-Notes 5-Aftertaste Not applicable for Not applicable Chalky, tannin and Slight-to-moderate Lingering unflavored products for unflavored drying mouthfeels intensity bitterness bitterness, products and moderate mouthfeels and intensity musty aromatic off-notes aromatic off-notes

The negative (aversive) sensory attributes of the micronized API (Formulation #4) are marginally above a slight (1) intensity, which is the perception threshold for most patients as shown in FIG. 13 .

Tecovirimat—Formulation 1 (Strawberry)

Tecovirimat Formulation #1 (Strawberry) is somewhat low in initial flavor quality as measured by Amplitude (balance and fullness) as shown in Table 49.

TABLE 49 Flavor Profile for Tecovirimat - Formulation 1 (Strawberry) Flavor Profile SIGA Tecovirimat Formulation #1 200 mg/mL (Strawberry) Initial 1 Min 3 Min 5 Min 10 Min 15 Min 20 Min 25 Min 30 Min Amplitude 1 Sweet 1½ 1-1½ ½-1 ½ 0-½ — — — — Sour ½ — — — — — — — — Strawberry 1½ 1 ½ — — — — — — Aromatics(Fresh and Cream) Chalky/Musty 1½ 1 ½ 0-½ — — — — — Aromatic Bitter 1 ½-1 ½ ½ 0-½ — — — — Chalky Mouthfeel 1 1 1 ½ — — — — — Tannin Mouthfeel ½-1 1 ½-1 ½ ½ 0-½ — — — Drying Mouthfeel — 1 1½ 1 1 1 1 ½ — Synthetic — ½-1 ½ 0-½ — — 1 — — Sweetener Sensation (SSS) Flavor Leadership Interpretation 1 - Aromatic Identity 2- Amplitude 3- Mouthfeel 4- Off-Notes 5-Aftertaste Slight-to-moderate A low level of Chalky, tannin, Slight intensity Lingering basic intensity strawberry balance and drying and SSS bitterness and tastes, aromatic off- flavoring aromatics fullness mouthfeels slight-to-moderate notes and intensity mouthfeels chalky/musty aromatic off-notes

The flavor system (flavoring aromatics and sweet basic taste) of Formulation #1 (Strawberry) provides reasonable coverage of the bitter basic taste and chalky/musty aromatics as shown in FIG. 14 .

Tecovirimat—Formulation 2 (Cherry)

As shown in Table 50, Tecovirimat Formulation #2 (Cherry) is slightly lower in initial flavor quality than the Formulation #1 (Strawberry) as measured by Amplitude.

TABLE 50 Tecovirimat - Formulation 2 (Cherry) Flavor Profile SIGA Tecovirimat Formulation #2 200 mg/mL (Cherry) Initial 1 Min 3 Min 5 Min 10 Min 15 Min 20 Min 25 Min 30 Min Amplitude ½-1 Sweet 1½ 1-1½ ½-1 ½ 0-½ 0-½ Sour ½ 0-½ — — — — — — — Strawberry 1½ 1 ½ — — — — — — Aromatics(Fresh and Cream) Chalky/Musty 1½ 1 ½ — — — — — — Aromatic Bitter 1 1 ½-1 ½ ½ — — — — Chalky Mouthfeel 1 1-½ 1 ½ — — — — — Tannin Mouthfeel 1 1-½ 1 ½ ½ 0-½ — — — Drying Mouthfeel — 1 1-1½ 1-1½ 1 1 1 ½ — Synthetic — 1 ½-1 ½ ½ — — — — Sweetener Sensation (SSS) Flavor Leadership Interpretation 1 - Aromatic Identity 2- Amplitude 3- Mouthfeel 4- Off-Notes 5-Aftertaste Slight-to-moderate A low level of Chalky, tannin, Slight intensity Lingering basic intensity strawberry balance and drying and SSS bitterness and tastes, aromatic off- flavoring aromatics fullness mouthfeels slight-to-moderate notes and intensity mouthfeels chalky/musty aromatic off-notes

The flavor system (flavoring aromatics and sweet basic taste) of Formulation #2 (Cherry) provides reasonable coverage of the bitter basic taste and chalky/musty aromatics as shown in FIG. 14 .

The results show that he unsweetened/unflavored Tecovirimat formulations are characterized by aromatic offnotes, (musty, chalky, soapy/waxy), bitter basic taste and tannin/chalky mouthfeels. However, overall, those attributes arc lower in intensity in the micronized API compared to the granules.

The negative attributes of the micronized API are near the perception threshold for most patients (i.e., may not be patient-perceptible).

The two sweetened/flavored Tecovirimat suspensions are somewhat low in overall flavor quality and both flavored suspensions are somewhat low in initial flavor quality as measured by Amplitude (Target=1.) due to their aromatic off-notes (chalky/musty), bitter basic taste and mouthfeels (tannin/chalky).

Both flavored suspensions arc somewhat low in flavor and sweetness impact (intensity). However the strawberry-flavored suspension is slightly more blended and full (i.e., higher in Amplitude) than cherry-flavored suspension, which was somewhat “solventy” (benzaldehyde-like) in character and both flavored suspensions provide a reasonable coverage of the bitter basic taste and chalky/musty aromatics, though the flavoring aromatics fade quickly.

Thus it can be seen that Tecovirimat is relatively “bland” in flavor (basic tastes, aromatics, mouthfeel and texture), with the micronized API having a lower flavor than the API granules and the sweetened/flavored formulations are somewhat low in flavor quality (strawberry higher than cherry), primarily due to low impact (intensity) and duration of the flavoring aromatics and to a lesser extent the underlying sweet basic taste.

While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made, and equivalents may be substituted, without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of tile invention.

REFERENCES

-   1. Fenner et al., The epidemiology of smallpox. In: Smallpox and its     eradication. Switzerland; World Health Organization; 1988) -   2. Bray et al., Antiviral Research 58: 101-114 (2003). -   3. Quenelle et al. 2007. Efficacy of delayed treatment with ST-246     given orally against systemic orthopoxvirus infections in mice.     Antimicrobial Agents and Chemotherapy February; 51(2):689-95 -   4. Smee et al. (2002) Antimicrob. Agents Chemother. 46:1329-1335) -   5. Vora et al., 2008, Severe eczema vaccinatum in a household     contact of a smallpox vaccine. Clinical Infectious Disease 15;     46(10):1555-61). 

1. A dry suspension comprising 4-trifluoromethyl-N-(3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2-(1H)-yl)-benzamide (Tecovirimat (ST-246)) and simethicone.
 2. A dry suspension according to claim 1 further comprising at least one suspending agent.
 3. A dry suspension according to claim 2 wherein the suspending agent is methylcellulose.
 4. (canceled)
 5. (canceled)
 6. A dry suspension according to claim 2 wherein the suspending agent is hydroxypropyl cellulose.
 7. (canceled)
 8. A dry suspension according to claim 1 further comprising a lubricant.
 9. A dry suspension according to claim 8 wherein the lubricant is magnesium stearate.
 10. A dry suspension according to claim 1 further comprising an excipient.
 11. A dry suspension according to claim 10 wherein the excipient is lactose monohydrate.
 12. A dry suspension according to claim 1 further comprising a further antifoaming agent.
 13. (canceled)
 14. (canceled)
 15. A dry suspension according to claim 1 wherein the ST-246 is selected from a group consisting of ST-246 polymorph Form I, ST-246 polymorph Form II, ST-246 polymorph Form II, ST-246 polymorph Form IV, ST-246 polymorph Form V and ST-246 polymorph Form VI.
 16. A dry suspension according to claim 1 wherein the ST-246 is micronized.
 17. A dry suspension according to claim 1 wherein the ST-246 is granulated.
 18. A dry suspension according to claim 1 wherein the simethicone is granular form.
 19. A dry suspension according to claim 1 wherein the simethicone is in liquid form and adsorbed on lactose monohydrate.
 20. (canceled)
 21. (canceled)
 22. A dry suspension according to claim 1 comprising 0.2 to 6.0 wt % simethicone.
 23. (canceled)
 24. A dry suspension according to claim 3 comprising 1 to 5 wt % methylcellulose.
 25. (canceled)
 26. A dry suspension according to claim 6 comprising 1.0 to 30 wt % hydroxypropylcellulose.
 27. (canceled)
 28. (canceled)
 29. (canceled)
 30. (canceled)
 31. (canceled)
 32. A dry suspension according to claim 1 wherein the particle size of ST-246 is 0.5 to 10 μm.
 33. (canceled)
 34. An aqueous pharmaceutical suspension formulation comprising a dry suspension according to claim 1 and water.
 35. A formulation according to claim 34 further comprising a pharmaceutically acceptable ingredient.
 36. A formulation according to claim 35 wherein the pharmaceutically acceptable ingredient is selected from the group consisting of carrier, excipient, diluent, additive, filler, lubricant and binder.
 37. (canceled)
 38. A method of treating orthopoxvirus infections and/or eczema vaccinatum comprising oral administration to a subject in need thereof a formulation according to claim
 34. 39. The method of claim 38, wherein the subject is administered 400 mg to 2000 mg daily of ST-246.
 40. (canceled)
 41. A process of making the dry suspension according to claim 1, comprising mixing ST-246 with simethicone and optionally at least one suspending agent, at least one lubricant, at least one excipient, at least one further anti-foaming agent, at least one sweetener and/or at least one flavoring.
 42. (canceled)
 43. (canceled)
 44. (canceled) 